How to add an email signature in Outlook desktop
Outlook for Windows is the client that breaks the most signatures, and not by accident: classic Outlook draws emails with the Microsoft Word engine, not with a browser. Word understands tables, inline styles and images with fixed dimensions, and almost nothing invented for the web since.
Two apps live side by side today: classic Outlook and the new Outlook for Windows. They are configured in different places, so the steps for both are below.
Classic Outlook
- 01
Copy your signature from SignatureForever with Outlook desktop as the destination.
- 02
In Outlook, open File › Options › Mail and click the Signatures button.
- 03
On the E-mail Signature tab, click New and type a name.
- 04
Paste the signature into the edit box with Ctrl+V.
- 05
On the right, under “Choose default signature”, pick the account and assign the signature to new messages and to replies or forwards.
- 06
Click OK in both windows.
New Outlook for Windows
- 01
Open Settings with the gear at the top right.
- 02
Go to Accounts › Signatures.
- 03
Create a new signature, paste with Ctrl+V, choose the defaults and save.
After pasting, look at the signature inside the Signatures window: that box already uses the Word engine, so what you see there is very close to what your Outlook recipients will see. If it already looks broken there, it won't get better when you send it.
SignatureForever exports two variants. Universal links images to their permanent address on our CDN and is the right choice almost every time. Embedded carries the images inside the signature: it works as an extra for Outlook desktop on restricted networks, but don't use it if your emails will reach Gmail.
What breaks in Outlook desktop and how to avoid it
The list below is the longest of the seven for one reason only: the Word engine. It knows neither flex nor grid, so columns stack. It ignores max-width and percentage widths, so the outer table needs a fixed pixel width. It doesn't apply border-radius, letter-spacing or text-transform, and it reserves the wrong space for any image without width and height attributes.
There is one piece of good news that confuses people: Outlook desktop does show base64 images. That is why an embedded signature looks perfect in your Outlook and arrives broken for anyone on Gmail.
| Feature | Outlook desktop |
|---|---|
| <table> layout | Yes |
| display:flex and CSS grid | × No |
| <style> block in the head | – Partial |
| background-image in CSS | × No |
| Images as data URI (base64) | Yes |
| border-radius | × No |
| letter-spacing | × No |
| text-transform:uppercase | × No |
| Web fonts (Google Fonts) | × No |
| max-width and percentage widths | × No |
| margin on <td> | × No |
| <img> without explicit width and height | × No |
In total: 9 unsupported, 1 partial and 2 fully supported, out of the 12 features in the matrix. Why each one fails, in the full matrix.
Common mistakes
Round photo that comes out square
border-radius does not exist for Word. If the photo must be round in Outlook, use an image already cropped into a circle on a white background.
Giant logo
An image without width and height shows at its real size. A 1200-pixel logo fills the whole screen.
Spacing that disappears
margin on a cell isn't honoured. Reliable spacing is padding inside the <td> or a spacer row with a fixed height.
Only setting up the new Outlook
If someone on your team still uses classic Outlook, their signature lives in File › Options › Mail › Signatures, not in the new one's.
Outer table without a fixed width
If the table is set to 100%, Word stretches it across the full width of the email. Give it a pixel width, 600 at most.
Frequently asked questions
Why does Outlook take my signature apart?
Because classic Outlook uses the Word engine, which doesn't understand flex, grid or max-width. A signature built with tables and fixed pixel widths doesn't have that problem.
Where do signatures go in the new Outlook?
In Settings › Accounts › Signatures. In classic Outlook, File › Options › Mail › Signatures.
How do I know what will break before I install it?
Paste your HTML into the free checker: it tells you what fails in Outlook desktop and how to fix it.
Are you an AI agent? This is also available as an MCP server at signatureforever.com/mcp