Why email signatures don't show on Outlook mobile (and how to fix it)
Your signature looks perfect in Outlook on your laptop. Then you reply from your phone and it's gone, or it says "Get Outlook for iOS" instead.
The short answer: Outlook for iOS and Android keeps its own signature, separate from desktop and web. The roaming signatures that sync between Outlook for Windows and Outlook on the web don't reach the mobile apps. So unless something sets the mobile signature for you, each phone has whatever was typed into it, or the app's default.
Below are the common causes, the fixes a user can make in two minutes, and the options for admins who want every phone in the organisation to send the right signature.
Why it happens
Symptom | Likely cause |
|---|---|
"Get Outlook for iOS" or "Get Outlook for Android" appears instead of your signature | The app's default signature is on and no custom one has been set on the phone |
Desktop signature never appears on the phone | Roaming signatures sync between Outlook for Windows and Outlook on the web, not to the mobile apps |
Signature appears but logo and formatting are missing | It was pasted into the mobile app, which handles rich HTML signatures poorly |
Right signature on one account, wrong on another | Per Account Signature is off, so every account on the phone shares one signature |
Company signature missing when sending as a shared mailbox | Outlook add-ins don't run for shared mailboxes on mobile |
Add-in signature missing after replying | You replied from the bottom of a message: the signature was added but isn't shown until you expand the compose window to full screen |
Add-in signature missing on emails started from the iOS Share sheet | The add-in event doesn't fire for messages created through Share on iOS |
Add-in signature never appears on mobile | The Outlook app is older than version 4.2352.0, the first to support event-based add-ins on iOS and Android |
Signature is on received emails but not visible when composing on the phone | It is added server-side by a mail flow rule or third-party service, so it never appears in compose or Sent Items |
Sources: Implement event-based activation in Outlook mobile add-ins and Outlook add-ins in shared folder and shared mailbox scenarios (Microsoft Learn); Roaming signature on Mac and mobile Outlook (Microsoft Q&A).
Fixes you can make on your phone
These take a couple of minutes and need no admin rights.
- Set a signature in the app. Open Outlook, tap your profile picture, then the Settings gear, then Signature. Type your signature and save. The menu layout varies slightly between iOS, Android and app versions.
- Turn on Per Account Signature if you have more than one account on the phone, then set a separate signature for each.
- Keep it simple. Logos, tables and coloured text pasted from desktop often break on mobile. A plain-text signature with your name, title, company and phone number is reliable.
- Update the Outlook app. If your company uses a signature add-in, older versions of the app won't run it.
- Expand the reply window. If you reply from the bottom of a message and can't see your signature, tap to open the compose window full screen. It is often there, just out of view.
- Start new emails in Outlook itself. On iOS, emails started from another app's Share button don't trigger signature add-ins.
The catch is that every one of these is per person, per phone. Change your job title or your company's address, and every phone needs updating by hand.
Fixes for admins, across the whole tenant
If you manage Microsoft 365 for an organisation, you want every phone to send the right signature without relying on users.
1. Turn off the "Get Outlook for iOS/Android" default. If you manage the app with Intune, set the app configuration key com.microsoft.outlook.Mail.DefaultSignatureEnabled to false. Users can still add their own signature. See Deploying Outlook for iOS and Android app configuration settings (Microsoft Learn).
2. Stamp signatures server-side with a mail flow rule. A rule adds the signature to every outgoing message, whatever device sent it. It's free, but the signature lands at the bottom of reply threads and the sender never sees it. Our post on adding a legal disclaimer in Microsoft 365 walks through the setup and the catches.
3. Use a signature add-in that supports Outlook mobile. Since Outlook for iOS and Android version 4.2352.0, add-ins can run automatically when a user composes an email on the phone. A centrally deployed add-in can replace whatever is set locally with the correct company signature, personalised from the directory. Two limits remain: add-ins don't run for shared mailboxes on mobile, and there is no manual fallback button on the phone if something fails.
Where Sigil fits. Sigil takes the third approach. One template, personalised from each person's Microsoft 365 profile, applied automatically in Outlook for Windows, Mac, web, iOS and Android, with a report showing which mailboxes have actually applied it. It costs £0.70 per mailbox per month, and there's a 14-day free trial with no card needed.
For the bigger picture, see our guide to managing Outlook signatures across Microsoft 365.