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How to Add an Email Signature in Exchange
Add an email signature in Exchange Online or Exchange Server with mail flow rules. Get steps, an HTML template, AD attributes, and fixes for duplicates.
Reading time:
14 min
Author: Amotz Harari
Updated: October 14, 2026
Short answer
How do you add an email signature in Exchange?
To add a company-wide email signature in Exchange, open the Exchange admin center, go to Mail flow > Rules, and create an Apply disclaimers rule with your HTML signature. Users can also set personal signatures in Outlook, or you can use a third-party tool.
Why copy-paste signatures turn Exchange admins into a helpdesk
Copy-paste signature policies fail the moment a company passes a few dozen people.
Someone pastes the wrong logo, someone else adds a quote, and new hires send unsigned email for weeks.
Then the requests land on IT.
I saw an Exchange admin in a forum sum it up well: “As the Exchange admin, I got stuck being the email signature designer and support desk.”
A mail flow rule fixes that in about 7 minutes, by Microsoft’s own estimate.
What Are Exchange Signatures
What is an Exchange email signature?
An Exchange email signature is an HTML or plain-text block that a mail flow rule (also called a transport rule) adds to messages as they pass through Microsoft Exchange. It applies to every user and device, with nothing to configure in Outlook.
Microsoft calls these organization-wide signatures “disclaimers,” whatever they contain.
Exchange signatures work in 1 of 2 places:
Server-side: Exchange adds the signature in transport, after the user clicks Send
Client-side: Outlook inserts the signature while the user writes the email
Server-side rules reach every device, including phones. The trade-off is that users never see the signature before it’s sent.
Setup Options
Which Exchange email signature setup do you need?
The right Exchange email signature setup depends on 2 questions. Is the signature for 1 person or the whole company? And are your mailboxes in Exchange Online, on-premises Exchange Server, or a hybrid of both?
Your situation
What to use
Where to start
Just my own signature
Personal signature in Outlook
Outlook personal signature steps below
Whole company on Exchange Online
Mail flow rule in the new Exchange admin center, or a third-party tool
Exchange Online tab below
Whole company on hybrid Exchange
Mail flow rules wherever outbound mail leaves, or a third-party tool
Both tabs below
Whole company on Exchange Server only
Mail flow rule in the Exchange Server admin center, or a tool that installs on-premises
Exchange Server tab below
Signatures under replies, visible in Sent Items, or edited by marketing
Third-party signature tool
Third-party tools section below
Hybrid deployments need extra care. Exchange Online mailboxes send outbound mail through Exchange Online by default. On-premises mailboxes send through Exchange Server.
So the rule must exist in both places. The exception is centralized mail transport, which routes all outbound mail through your on-premises servers.
Signature Content
What should an Exchange email signature include?
An Exchange email signature should identify the sender, their role, and how to reach them, in 3-4 clean lines. Exchange fills most of these fields automatically from Active Directory or Microsoft Entra ID, using tokens like %%DisplayName%% and %%Title%%.
Essential elements (and the Exchange token that fills each one):
Full name: top line, bold, slightly larger (%%DisplayName%%)
Job title and department: the sender’s role and team (%%Title%%, %%Department%%)
Company name: linked to your website (%%Company%%)
Contact details: direct phone and email (%%Phone%%, %%MobilePhone%%, %%WindowsEmailAddress%%)
Optional additions:
Logo or headshot: kept small, around 100-150 pixels square
Social icons: 2-3 profiles at most, such as LinkedIn
Call to action: 1 text link, such as a calendar booking page
Design rules that keep it readable:
Length: 3-4 lines of text
Colors: 2 brand colors at most
Fonts: web-safe fonts like Arial, Calibri, or Aptos
Images: never make the whole signature 1 image
Image-only signatures get flagged by spam filters, and their links don’t work on phones.
How do Outlook, mail flow rules, and third-party tools compare for Exchange signatures?
Outlook signatures, Exchange mail flow rules, and third-party tools are the 3 ways to add a signature in Exchange. Outlook is per user and manual. Mail flow rules are central and free but invisible to senders. Third-party tools add central control with compose-time visibility.
How do you add a personal signature in Outlook for an Exchange account?
A personal Outlook signature is the fastest option when only 1 person needs a signature. Each user creates it in Outlook settings, and it applies only to that user’s account on that client.
In new Outlook and Outlook on the web:
Open Settings > Accounts > Signatures
Select Add signature and give it a name
Format your text, links, and images
Choose default signatures for new messages and for replies or forwards
Save
The catch is maintenance. Every user does this manually, and Outlook mobile signatures are set up separately.
How do you add a company-wide signature in Exchange?
A company-wide signature in Exchange is a mail flow rule that uses the Apply disclaimers action. You build it in the Exchange admin center (EAC), choose who it applies to, paste your HTML, and set a fallback action.
The click path differs between the new Exchange Online EAC and the classic Exchange Server EAC. Pick your environment:
How to add a company-wide signature in Exchange Online
Sign in to the Exchange admin center at admin.exchange.microsoft.com. You can also go to the Microsoft 365 admin center > Show all > Exchange.
Go to Mail flow > Rules.
Select + Add a rule > Apply disclaimers, and name the rule.
Under Apply this rule if, choose Apply to all messages. For external mail only, choose The recipient > is external/internal > Outside the organization.
Under Do the following, keep Apply a disclaimer to the message > append a disclaimer. Choose prepend to place it at the top instead.
Select Enter text, paste your HTML signature, and save.
Select Select one and choose a fallback action.
Under Except if, add the duplicate-signature exception described below.
On Set rule settings, choose a rule mode (Enforce, or a test mode first). Leave Match sender address in message at Header.
Review the rule and select Finish.
How to add a company-wide signature in Exchange Server SE, 2019, and 2016
Open the Exchange admin center at https://<your-server>/ecp.
Go to Mail flow > Rules.
Select + (New) > Apply disclaimers…, and name the rule.
Select More options to unlock exceptions and extra conditions.
Under Apply this rule if, choose [Apply to all messages] or The recipient is located > Outside the organization.
Under Do the following, choose Append the disclaimer.
Select Enter text, paste your HTML signature, and save.
Select Select one and choose a fallback action.
Select Add exception and add the duplicate-signature exception.
Choose a mode (Enforce, Test with Policy Tips, or Test without Policy Tips) and select Save.
Exchange 2013 uses the same EAC flow as Exchange Server 2016.
Exchange 2010 uses the Exchange Management Console (Organization Configuration > Hub Transport > Transport Rules) or the Exchange Management Shell.
Version Support
Is your Exchange Server version still supported?
Exchange Server 2016 and 2019 reached the end of extended support on October 14, 2025. Exchange Server Subscription Edition (SE) is the supported on-premises version. The signature steps above work the same on 2016, 2019, and SE.
Microsoft sold a paid Extended Security Update (ESU) program to buy migration time:
Period 1: October 2025 to April 2026
Period 2: May 2026 to the end of October 2026
Eligibility: Enterprise Agreement customers only, purchased separately for each period
Microsoft’s Exchange Team says there will be no further extensions. They also state that ESU “is not an extension of the support lifecycle.”
Exchange 2013 and 2010 are long out of support.
Microsoft recommends moving 2016 servers to the latest Exchange 2019 cumulative update, then upgrading in place to SE, or migrating to Exchange Online.
Powershell Setup
How do you create an Exchange signature rule with PowerShell?
An Exchange signature rule in PowerShell uses the New-TransportRule cmdlet. The same command works in Exchange Online PowerShell and the Exchange Management Shell, which makes the rule easy to repeat, document, and roll back.
Applies the signature to external recipients only. Remove it to sign all mail
-ApplyHtmlDisclaimerLocation
Append adds the signature at the bottom. Prepend adds it at the top
-ApplyHtmlDisclaimerFallbackAction
What happens when Exchange can’t modify the message: Wrap, Ignore, or Reject
-ExceptIfSubjectOrBodyMatchesPatterns
Skips messages that already contain your signature, which prevents duplicates
-ApplyHtmlDisclaimerText
The HTML signature, including %%tokens%%
Use Get-TransportRule to review existing rules and Set-TransportRule to edit one.
Signature Attributes
Which attributes and HTML can an Exchange signature use?
Exchange signature rules accept HTML, inline CSS, and 23 tokens that pull the sender’s details from Active Directory or Microsoft Entra ID. On Exchange Server, Microsoft caps disclaimer text at 5,000 characters, including all HTML tags and inline CSS.
Supported Exchange signature tokens
Exchange signature tokens are placeholders wrapped in double percent signs. Exchange swaps each one for the sender’s directory value at send time.
Replace the logo URL, brand color, website, and footer line with your own
Keep the footer line unique, because the duplicate-signature exception matches it
Avoid tokens for fields that are often empty, such as %%MobilePhone%%
Skip external stylesheets, scripts, and web fonts
Can you add a logo to an Exchange email signature?
Logos in an Exchange email signature work only as hosted images linked with an IMG tag. Exchange can’t embed images in the message itself.
Microsoft also notes that Outlook and Outlook on the web block external images by default.
Recipients see your logo only after they download the external content. Test the result before you enforce the rule.
Fallback Actions
Which fallback action should an Exchange signature rule use?
The fallback action tells Exchange what to do when it can’t add the signature, usually because the message is encrypted. Exchange offers 3 options: Wrap, Ignore, and Reject. For an outbound signature rule, Ignore is the safest choice.
Fallback option
What happens
Use it when
Risk
Wrap (the default)
Exchange creates a new message, attaches the original, and adds the signature to the new one
A disclaimer must appear on every message, even encrypted ones
Recipients get an attachment. If wrapping fails, the sender gets a non-delivery report (NDR)
Ignore
Exchange sends the original message without the signature
A missing signature is acceptable on the occasional encrypted email
Some messages go out unsigned
Reject
Exchange returns the message to the sender in an NDR
Policy forbids sending anything without the disclaimer
Legitimate mail gets blocked
Microsoft adds 1 warning for Exchange Online.
Don’t use Wrap in rules covering inbound mail from external senders. Wrap interferes with Safe Attachments scanning.
Duplicate Signatures
How do you stop Exchange from adding the signature twice?
Duplicate Exchange signatures happen because the rule fires on every message, including replies to emails that already carry the signature. The fix is an exception that skips any message already containing a unique line from your signature.
Open the rule and go to Except if
Choose The subject or body > Subject or body matches these text patterns
Enter a phrase that only appears in your signature, such as your registered-office line
Save the rule
Reply to and forward a test message to yourself, and check for a duplicate
Check rule overlap as well. Overlapping rules for the same sender also produce doubles.
Review rule priority under Mail flow > Rules.
Long threads are where admins notice this most.
An IT pro I saw in a forum put it bluntly: “For Pete’s sake, you don’t need the images, website link or newsletter sign-up in replies.”
Native Limits
What can’t Exchange mail flow rule signatures do?
Exchange mail flow rule signatures can’t place the signature under the latest reply, show it in Sent Items, or hide lines with missing directory values. Microsoft lists these limits in its own Exchange Server and Microsoft 365 documentation.
The full list of native limits:
Thread placement: the signature lands at the end of the whole message, under the quoted history
Sent Items: senders never see the server-side signature in their own copy
Empty fields: a line with an empty token still renders, blank or half-filled
Images: logos must be hosted and linked, never embedded
Editing: no visual editor or preview, just raw HTML in a text box
Encryption: encrypted messages trigger the fallback action
Ownership: every change needs someone with Exchange admin rights
New Outlook: users can’t see the signature while writing
The Sent Items gap causes the most trouble in practice.
I saw an IT pro describe it in a forum thread: “Users couldn’t see the signature while composing, so they kept adding their own and breaking everything.”
Microsoft’s own docs point admins to third-party email signature tools to close these gaps.
Third-Party Tools
What are the best third-party tools for Exchange email signatures?
Third-party tools for Exchange email signatures fix what mail flow rules can’t. They place signatures under the latest reply, show them while users write, and sync details from your directory. WiseStamp, Exclaimer, and CodeTwo are the most common choices.
WiseStamp (best overall for Exchange Online and hybrid): WiseStamp’s Outlook add-in inserts the signature while the user writes, so it sits under the reply and shows in Sent Items. Server-side routing covers phones and every other client. Hybrid mode runs both and only adds a server-side signature when none is found, so there are no doubles. Employee details sync from Microsoft Entra ID, and WiseStamp states it doesn’t read or store email content.
Exclaimer: a widely used signature service for Microsoft 365 and Exchange, with a separate product for on-premises Exchange Server.
CodeTwo: signature tools for Microsoft 365, plus a separate on-premises product for Exchange Server.
Check your topology before you choose. WiseStamp needs Exchange Online or hybrid Exchange with identity in Microsoft Entra ID. It doesn’t support on-premises-only Exchange Server.
On plans, the Outlook add-in and Entra ID sync start on Basic. Server-side routing and hybrid mode need Platform or Enterprise.
A missing Exchange email signature usually comes down to the rule’s mode, its conditions, or its priority. Duplicates, missing images, and blank lines each have their own cause. Use this table to match the symptom to the fix.
Symptom
Likely cause
Fix
No signature on sent mail
Rule disabled, in test mode, or conditions don’t match
Set the rule to Enforce and recheck the Apply this rule if condition
Signature added only sometimes
A higher-priority rule has Stop processing more rules turned on
Reorder rules under Mail flow > Rules
Signature appears twice
No exception, or 2 rules match the sender
Add the text-pattern exception and remove overlapping rules
Signature at the bottom of the thread
Expected behavior for append rules
Use prepend, or a tool with an Outlook add-in
Logo missing
Image not hosted over HTTPS, or blocked by the recipient’s client
Host the image publicly and test in Outlook and Gmail
Blank line in the signature
Empty directory field behind a token
Fill the field in Active Directory or Entra ID, or remove the token
Recipient gets an attachment
Wrap fallback triggered by an encrypted message
Switch the fallback to Ignore for outbound signature rules
Users still add their own signature
They can’t see the server-side signature
Tell users about the change, or use an add-in that shows it
Adding an email signature in Exchange takes 1 mail flow rule. Use Apply disclaimers in the Exchange admin center, paste HTML with %%tokens%% for each sender’s details, set the fallback to Ignore, and add a text-pattern exception against duplicates.
That rule is free and covers every device. It can’t put the signature under replies, show it in Sent Items, or hide empty fields.
When those gaps start generating tickets, a tool with an Outlook add-in and directory sync is the next step.
An Exchange admin adds a company-wide email signature with a mail flow rule in the Exchange admin center:
Go to Mail flow > Rules
Add a rule using Apply disclaimers
Choose which senders or recipients the rule covers
Paste the HTML signature and set a fallback action
Add an exception against duplicates, then enforce and test
Yes. A mail flow rule in the Exchange admin center adds 1 signature to every Microsoft 365 sender at no extra cost, and Microsoft estimates about 7 minutes to set up. The trade-off is that users can’t see the signature while writing, and the signature doesn’t appear in Sent Items.
Yes. Set the Exchange rule condition to The recipient > is external/internal > Outside the organization. In PowerShell, add -SentToScope NotInOrganization to New-TransportRule. Internal mail then goes out without the signature.
An Exchange admin changes the signature by editing the mail flow rule that adds it:
Open the Exchange admin center and go to Mail flow > Rules
Open the signature rule
Replace the HTML under Enter text
Save, then send a test email
In PowerShell, Set-TransportRule edits the same rule.
An Exchange email signature is an HTML or plain-text block that a mail flow rule adds to messages as they pass through Microsoft Exchange. Microsoft calls these organization-wide signatures disclaimers, whatever they contain.
Each user adds a personal signature in new Outlook or Outlook on the web:
Open Settings > Accounts > Signatures
Select Add signature and name it
Format the text, links, and images
Pick defaults for new messages and for replies or forwards
Outlook mobile signatures are set up separately.
Yes. Microsoft’s Exchange Server signature documentation applies to Exchange Server SE, 2019, and 2016, and the Exchange admin center steps are the same across all 3 versions.
No. Exchange Server 2016 and 2019 reached the end of extended support on October 14, 2025, according to Microsoft’s lifecycle pages. Paid Extended Security Updates ran in 2 periods through the end of October 2026, for Enterprise Agreement customers only. Exchange Server SE is the supported on-premises version.
No. An Exchange mail flow rule adds the signature after the user clicks Send, so new Outlook never shows it while the user writes. Recipients still see the signature. The sender’s copy in Sent Items doesn’t include it.
Use the New-TransportRule cmdlet in Exchange Online PowerShell or the Exchange Management Shell. The key parameters are:
-ApplyHtmlDisclaimerText: the HTML signature with tokens
-ApplyHtmlDisclaimerLocation: Append or Prepend
-ApplyHtmlDisclaimerFallbackAction: Wrap, Ignore, or Reject
-ExceptIfSubjectOrBodyMatchesPatterns: a unique line that prevents duplicates
Exchange email signatures support 23 tokens that pull sender details from Active Directory or Microsoft Entra ID. Common tokens include:
%%DisplayName%% and %%Title%%
%%Department%% and %%Company%%
%%Phone%% and %%MobilePhone%%
%%WindowsEmailAddress%%
Exchange Server caps signature text at 5,000 characters, including HTML and inline CSS.
Yes, but only as a hosted image linked with an IMG tag. Exchange can’t embed images in the message. Microsoft notes that Outlook and Outlook on the web block external images by default, so recipients see the logo only after downloading external content.
No. An image-only email signature gets flagged by spam filters, and its links don’t work on phones. Use 3-4 lines of real text, a small logo of about 100-150 pixels, and web-safe fonts like Arial, Calibri, or Aptos.
Exchange can’t add a signature to an encrypted message, so the rule’s fallback action decides what happens:
Wrap: the original is attached to a new message that carries the signature
Ignore: the message goes out without the signature
Reject: the sender gets a non-delivery report
Ignore is the safest choice for outbound signature rules.
Add an exception that skips messages already containing the signature:
Open the rule and go to Except if
Choose Subject or body matches these text patterns
Enter a phrase that only appears in the signature
Reply to and forward a test email to confirm
Also check that only 1 rule matches each sender.
Users can’t edit a mail flow rule signature, because only someone with Exchange admin rights can change the rule. Users can still add a personal Outlook signature on top of it, which causes doubles. Tell users about the change, or use an Outlook add-in that shows the signature.
In Microsoft Exchange, a disclaimer and a signature use the same mechanism. Microsoft calls any organization-wide text added by a mail flow rule a disclaimer. The content decides the label. A legal footer and a full contact signature both use the Apply disclaimers action.
Microsoft documents several limits for Exchange mail flow rule signatures:
Place the signature under the latest reply
Show the signature in the sender’s Sent Items
Skip lines whose directory field is empty
Embed images instead of linking them
Every change also needs someone with Exchange admin rights.
The most common third-party tools for Exchange email signatures are:
WiseStamp: Outlook add-in, server-side routing, and Entra ID sync for Exchange Online and hybrid Exchange
Exclaimer: a Microsoft 365 service plus a separate on-premises Exchange Server product
CodeTwo: Microsoft 365 tools plus a separate on-premises Exchange Server product
WiseStamp doesn’t support on-premises-only Exchange Server.
A missing Exchange email signature usually has 1 of 3 causes:
The rule is disabled or still in a test mode
The rule’s conditions don’t match the message
A higher-priority rule stops processing first
Set the rule to Enforce and review rule order under Mail flow > Rules.
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