How to Add Your Signature to Outlook (All Versions Covered)

Adding a signature in Outlook is one of those setup tasks that looks straightforward until you realize there are several versions of Outlook, multiple ways to trigger signatures, and a handful of settings that interact with each other in ways that aren't always obvious. Here's a clear breakdown of how it works — and what to watch for depending on your setup.

What an Outlook Signature Actually Does

An Outlook signature is a block of text (and optionally images or links) that gets automatically appended to your emails. You can set it to appear on new messages, replies and forwards, or both — and you can create multiple signatures and switch between them manually when composing.

Signatures are stored locally in the desktop versions of Outlook, but managed through account settings in the web and mobile versions. That distinction matters, because a signature you set up in Outlook desktop won't automatically appear in Outlook on the web, and vice versa.

How to Add a Signature in Outlook Desktop (Windows)

This applies to Outlook for Microsoft 365, Outlook 2021, 2019, and 2016 on Windows. The steps are nearly identical across these versions.

1. Open Outlook and click File → Options
2. Select Mail from the left panel
3. Click the Signatures… button
4. In the Signatures and Stationery window, click New to create a signature
5. Give it a name (e.g., "Work" or "Personal")
6. Type your signature in the editor — you can format text, add links, and insert images
7. Under Choose default signature, set which email account it applies to and whether it appears on New messages and/or Replies/forwards
8. Click OK to save

✍️ The editor is basic but functional. If you want a more polished HTML signature with logos or complex formatting, you may need to design it externally and paste it in — or use an HTML import method.

How to Add a Signature in Outlook on the Web (OWA)

If you're using Outlook through a browser at outlook.live.com or your organization's Microsoft 365 web portal:

1. Click the Settings gear (top right)
2. Select View all Outlook settings at the bottom of the panel
3. Go to Mail → Compose and reply
4. Under Email signature, type or paste your signature
5. Toggle on Automatically include my signature on new messages and/or replies and forwards as needed
6. Click Save

Changes here apply only to your web experience. They don't sync to the desktop app.

How to Add a Signature in Outlook for Mac

The Mac version of Outlook has a slightly different navigation path:

1. Open Outlook and go to Outlook (menu bar) → Preferences
2. Click Signatures
3. Click the + button to add a new signature
4. Name it and compose the content in the editor
5. Drag the signature name to the account you want it associated with
6. Set your default for new messages and replies using the dropdown menus

Note: Outlook for Mac stores signatures differently than Windows, and formatting compatibility between the two can occasionally cause visual inconsistencies if you're working across both platforms.

How to Add a Signature in the Outlook Mobile App 📱

On iOS or Android, Outlook includes a simple signature setting:

1. Tap your profile icon (top left)
2. Tap the Settings gear (bottom left)
3. Scroll to Signature
4. Toggle on Per Account Signature if you want different signatures per account, or edit the default
5. Type your signature and save

Mobile signatures are plain text only — no rich formatting, HTML, or images. They're independent of your desktop and web signatures.

Key Variables That Affect Your Setup

When Signatures Don't Show Up — Common Causes

• You set the signature in desktop Outlook but are checking mail in a browser
• The signature was assigned to the wrong account
• Your organization uses server-side signature injection, which adds signatures after sending — meaning you won't see them in your compose window
• You're replying in plain text mode, which strips HTML formatting from your signature

The Part That Depends on Your Situation

The technical steps above cover the mechanics across every major Outlook surface. But how you should actually configure your signature — how many you need, what they should contain, which accounts they're tied to, and whether you need them on replies — depends entirely on how you use email.

A freelancer managing three client accounts has very different needs than someone with a single corporate inbox managed by an IT department. And if your organization controls Microsoft 365 policies, some of these settings may not be fully in your hands to begin with.

Understanding where your signature lives — and which version of Outlook you're actually using day-to-day — is the starting point for getting this right.