How-to guide
How to add a signature in Outlook
Outlook exists in three flavors — new Outlook, classic desktop Outlook, and Outlook on the web — and the signature setting sits in a slightly different place in each. Here's the path for all three, plus how to drop in an image signature.
Before you start: you'll need your signature as an image. The email signature generator produces an Outlook-ready footer you can paste directly into the signature editor — free, no account, and nothing you type leaves your browser.
Why Outlook signatures are more confusing than they should be
Microsoft currently ships three different Outlooks — classic desktop Outlook (the one businesses have used for decades), new Outlook for Windows (the redesigned app rolling out since 2023), and Outlook on the web. They look similar but store signatures in different places: classic Outlook keeps them in local files on that specific PC, while new Outlook and the web version store them in your Microsoft 365 account in the cloud, where they roam between devices.
That storage difference explains almost every Outlook signature mystery. Set up a beautiful signature in classic Outlook at the office and it will not appear on your laptop at home; set one up in new Outlook and it appears everywhere new Outlook and the web app run — but still not in classic Outlook. If you use more than one flavor, plan to configure the signature twice.
Outlook is also the client where image rendering matters most. The Windows desktop versions render email with Word's engine, which handles images differently from the browser-based versions — it may resize them to 96 DPI or convert embedded formats. The safest input is a modest-sized transparent PNG created at roughly the display size you want, like the ones from the email signature generator.
Step by step
New Outlook and Outlook on the web
Click the gear icon → Mail → Compose and reply. Under Email signature, click + New signature, name it, and build it in the editor. Both versions share the same settings screen.
Classic desktop Outlook
Go to File → Options → Mail → Signatures…. Click New, name the signature, and compose it in the editor. Classic Outlook stores signatures per email account, so pick the right account in the dropdown first.
Insert your signature image
In any of the three editors, use the image icon to insert your signature PNG. A transparent PNG avoids the white rectangle you get with JPG. Keep the image under about 300 pixels wide so it doesn't dominate the email.
Set default signatures
Choose which signature applies to New messages and which to Replies/forwards. If you skip this, Outlook creates the signature but never uses it automatically.
Save and test
Save, then compose a new email to yourself. Check how the signature renders — Outlook on Windows uses Word's rendering engine, which can size images differently than the web version.
Troubleshooting
Signature exists but never appears automatically
The defaults dropdowns are set to (none). In classic Outlook: File → Options → Mail → Signatures → "Choose default signature". In new Outlook/web: Settings → Compose and reply → "Select default signatures". Assign your signature to New messages at minimum.
Signature missing on another computer
Classic desktop Outlook stores signatures locally per machine. Either recreate it (copy-paste from a sent email is fastest) or switch to new Outlook, where signatures roam with your account.
Image arrives stretched or pixelated
Word's rendering engine scales images. Export the signature PNG at close to its final display size (300–400px wide) instead of a large canvas that gets shrunk, and insert it rather than pasting from another app.
Wrong signature attached to the wrong account
Classic Outlook assigns signatures per email account via the dropdown at the top of the Signatures dialog. Check that each account has its own signature selected — the dialog silently shows only one account at a time.
Best practices
- If your company uses Microsoft 365, ask IT whether a server-side signature policy exists before perfecting your own — organization-wide policies can override or duplicate personal signatures.
- Keep the total signature under about 10 KB of HTML plus one small image; oversized signatures get clipped in Gmail when your recipients read there.
- Recreate rather than copy from Word — pasting from Word carries hidden markup that breaks in other mail clients.
- After setup, send a test to a Gmail address: Outlook-to-Gmail is the rendering combination that exposes most layout problems.
Common questions
Why does my Outlook signature look blurry?
Outlook sometimes scales images to 96 DPI. Export your signature at roughly the display size you want (300–400px wide) rather than a huge canvas that Outlook shrinks, and use PNG rather than JPG.
Do signatures sync between Outlook versions?
In new Outlook and the web app, signatures are stored with your Microsoft 365 account and roam. Classic desktop Outlook stores them locally per machine, so you may need to recreate the signature on each computer.
Can I have different signatures for different accounts?
Yes. Classic Outlook assigns signatures per account in the Signatures dialog; in new Outlook/web, switch accounts in settings and create a signature under each.
How do I add a signature in Outlook mobile?
In the Outlook app: Settings → tap your account → Signature. Like Gmail's app, it's a separate setting from desktop and starts as "Get Outlook for iOS/Android" until you change it.
Can I use HTML directly in an Outlook signature?
Not through the UI. Classic Outlook technically reads HTML files from the local Signatures folder (%APPDATA%\Microsoft\Signatures), which advanced users edit directly — but for most people, composing in the editor and pasting formatted content achieves the same result more safely.
Why does Outlook remove my signature when replying inline?
Inline replies inside the reading pane use the Replies/forwards default. If that's set to (none), inline replies go unsigned — assign your short signature to Replies/forwards in the same defaults dropdown.