How to Add an Email Signature in Outlook (Web, Mac & Windows)
Outlook keeps its signature settings in a different place on every platform, and its Word-based rendering has opinions about your images. Here's each platform, step by step.
Step by step
Outlook on the web: open settings
Click the gear icon (top right) → Mail → Compose and reply. The Email signature editor is at the top.
Create and name the signature
Click + New signature, name it, and build it in the editor.
Set the defaults
Below the editor, choose which signature applies For New Messages and For Replies/Forwards — then Save.
New Outlook for Mac
Menu bar Outlook → Settings → Email → Signatures. Click + to create, then assign defaults per account at the bottom of the window.
Classic Outlook for Windows
File → Options → Mail → Signatures… opens the same three-part dialog Office has had for a decade: create, edit, and assign per account.
Add images carefully
Outlook's desktop apps render email with Word's engine: use images at their exact display size (oversized images get scaled blurry), keep layouts table-based, and prefer hosted images so they update everywhere.
Send yourself a test
Check it in at least one other client (Gmail or Apple Mail) — Outlook-to-Outlook can look fine while everything else breaks, and vice versa.
Design once, paste everywhere
Autograph builds an Outlook-safe signature (tested against Word's rendering engine), installs it into Apple Mail in one click, and its Copy HTML button pastes cleanly into Outlook and Gmail.
Download Autograph free See the templatesCommon questions
Why is my Outlook signature missing on replies?
Replies use their own default. On the web: Compose and reply → For Replies/Forwards. On desktop: the Signatures dialog has separate New messages / Replies dropdowns per account.
Why does my logo look blurry in Outlook?
Outlook (Word engine) scales images by DPI and dislikes oversized sources. Use an image saved at the exact pixel size it displays at, or a properly sized hosted image — which is how Autograph exports signatures.
Do signatures sync between Outlook platforms?
Microsoft 365 roams web signatures in some tenants, but desktop and mobile frequently keep their own. Treat each platform's signature as separate and paste the same HTML into each.