New Outlook vs Classic Outlook: How to Add an Email Signature in Both

Microsoft now ships two very different applications under the same name. Half the instructions online describe menus that no longer exist in the version you are running.

This guide covers both, tells you how to work out which one you have, and explains what happens to your signature when you switch.

How to tell which Outlook you have

Look at the top-right corner of the window. If there is a toggle labelled New Outlook, you are in the classic desktop application. If the toggle is switched on, or there is no File menu in the top-left, you are in new Outlook.

New Outlook is essentially Outlook on the web wrapped in a desktop shell, which is why its settings look nothing like the old ones.

Adding a signature in new Outlook

The same steps work in new Outlook for Windows and in Outlook on the web.

1. Click the gear icon in the top-right corner
2. Go to Accounts → Signatures
3. Click New signature and give it a name
4. Build or paste your signature into the editor
5. Under Select default signatures, choose which one applies to new messages and which to replies and forwards
6. Click Save

If you are pasting a signature you built elsewhere, copy it from a rendered preview in your browser rather than copying raw HTML code.

Adding a signature in classic Outlook

1. Go to File → Options → Mail
2. Click the Signatures button
3. Click New, name the signature, and build it in the editor below
4. On the right, set the defaults for New messages and Replies/forwards
5. Click OK

There is a faster route: start a new email, click Signature on the Message ribbon, and choose Signatures from the dropdown.

Outlook for Mac

Open Outlook → Settings → Signatures, click the plus button, and build the signature. Assign defaults per account in the same panel.

Mac Outlook has its own quirks with pasted HTML, particularly around table spacing. Always send yourself a test message before rolling a signature out to a team.

Where signatures are stored, and why it matters

Classic Outlook stores signatures as local files on your machine, in %APPDATA%\Microsoft\Signatures, as a set of .htm, .rtf and .txt files for each signature.

New Outlook stores signatures server-side, attached to the mailbox. That means they follow you to any device you sign into — but it also means they do not roam across to classic Outlook, and they are not simply sitting in a folder you can edit.

Moving a signature from classic to new Outlook

There is no import button. The reliable method is to copy the rendered signature rather than the file.

1. In classic Outlook, start a new email so the signature appears
2. Select the whole signature and copy it
3. Switch to new Outlook, open the signature editor, and paste
4. Check images, spacing and link colours carefully

Expect to do some cleanup. Which brings us to the next point.

What tends to break in new Outlook

New Outlook renders signatures with a web engine rather than the Word engine classic Outlook uses. Most of the time this is an improvement, but signatures built for the old renderer can shift.

The things to check after migrating:

• Nested tables used for spacing may collapse or expand
• Images embedded as attachments in the old signature will not carry over — use hosted images
• Fixed pixel widths set for the old renderer can behave differently
• Font fallbacks may resolve to a different typeface

If images disappear entirely during the move, our guide to signature images not showing covers the likely causes.

Build once, use in both

A signature made with the Mail Ink generator uses clean, table-based HTML with hosted images, which renders consistently in classic Outlook, new Outlook, Outlook on the web and Outlook for Mac. You build it once and paste the same thing wherever you need it.