How to Add a Signature in Outlook (New, Classic, Web, Mac, Mobile)

To add a signature in Outlook, open Settings > Accounts > Signatures in the new Outlook for Windows or Outlook on the web, or go to File > Options > Mail > Signatures in classic Outlook for Windows. Create and name the signature, then choose whether Outlook inserts it automatically on new messages, replies and forwards.

The exact steps depend on which Outlook you’re using, and Microsoft currently ships several. Below are the official routes for each one as of October 2026, plus how defaults and syncing work. Menu labels shift between builds, so if a button has moved slightly, look for the nearest match.

First, figure out which Outlook you have

Microsoft’s support pages note that the signature steps are the same in the new Outlook for Windows and Outlook on the web, so one set of instructions covers both.

New Outlook for Windows and Outlook on the web

According to Microsoft’s Outlook signature guide, you can create several signatures and pick one when composing.

1. Select Settings (the gear icon).
2. Go to Accounts > Signatures.
3. If you have more than one account connected, choose the account you’re setting up.
4. Select New signature and give it a distinct name, such as “Full” or “Reply”.
5. Type and format your signature in the editor. You can add links and images here.
6. Under the default settings, choose which signature to use for new messages and which for replies and forwards. Leave them blank if you’d rather insert signatures by hand.
7. Select Save.

Some older Microsoft articles for Outlook on the web point to Mail > Compose and reply instead. If your tenant still shows that layout, the signature box and the “automatically include” checkboxes are on that page. See Microsoft’s Outlook on the web article for that variant.

Inserting a signature manually

If you didn’t set a default, or you want a different signature for one email:

1. Start a new message or reply.
2. On the Message tab, select Signature.
3. Pick the signature you want.

Classic Outlook for Windows

Classic Outlook keeps signatures in the Signatures and Stationery dialog. Microsoft’s default signature article describes this route:

1. Select File > Options.
2. Choose Mail, then select Signatures.
3. Select New, type a name for the signature and select OK.
4. Write and format the signature in the Edit signature box.
5. Under Choose default signature, pick the email account, then use the New messages and Replies/forwards drop-downs to choose which signature appears on each.
6. Select Save, then OK.

You can also reach the same dialog from a new message window: on the Message tab, select Signature > Signatures. Depending on your window size, the Signature button may sit in a slightly different place on the ribbon.

Adding a logo or image

In the signature editor, use the picture button to insert an image, then resize it with the picture options. Microsoft warns that signatures containing Vector Markup Language (VML) tags can cause some elements to show up as attachments rather than inline images, which is a common cause of “my logo arrives as an attachment” complaints. A third-party guide also mentions reports in 2026 of signature images failing to display after certain classic Outlook updates. We couldn’t confirm that in Microsoft’s documentation, so treat it as unverified and check that your Outlook is fully updated if images go missing.

Editing an existing signature

Go back to File > Options > Mail > Signatures, select the signature in the list, make your changes, then select Save and OK. Microsoft notes that a new or edited default signature is not added to a message you already have open, so insert it manually there.

Outlook for Mac

Steps here come from secondary guides, and they disagree slightly on the menu name. Make Tech Easier calls it Settings, while ASK4’s help article calls it Preferences. Recent macOS versions renamed Preferences to Settings across many apps, so you’ll see one or the other.

1. In the menu bar, select Outlook > Settings (or Preferences).
2. Select Signatures.
3. Select the + button to add a new signature, name it and format it in the editor.
4. Choose your default signature for new messages and for replies/forwards for each account.
5. Close the window to save.

Outlook mobile (iPhone, iPad and Android)

The mobile app has its own, simpler signature setting:

1. Open the Outlook app and tap the menu (your account icon or the menu button at the top-left).
2. Tap the Settings gear.
3. Tap Signature (some versions label it Email Signature).
4. Type your signature and go back to save.

Mobile signatures are more limited in formatting than desktop ones, so many IT departments recommend keeping them short, such as name, title and phone number.

Will my signature sync across devices?

This is where most confusion comes from, and the answer depends on your account and Outlook version.

• New Outlook for Windows and Outlook on the web share the same settings for a Microsoft 365 or Outlook.com account, so a signature created in one shows up in the other.
• Classic Outlook for Windows historically stored signatures on the computer only. Microsoft’s roaming signatures article says that from build 2303 onward, signatures are stored in your mailbox so they’re available on any device where that account is configured. No setup is needed, and existing signatures aren’t overwritten.
• Roaming has limits. Per Microsoft, it works for Microsoft 365 and Outlook.com mailboxes. Exchange on-premises, third-party email, and POP/IMAP accounts can’t roam signatures. Non-default signatures may stay on the device under “Signatures on this device”.
• Mobile is inconsistent. Some sources say a signature set in Outlook on the web syncs to the app automatically; others say each platform needs to be set up separately. If your phone isn’t showing the right signature, set it directly in the app.

Organizations can also manage or disable roaming signatures centrally, and some use server-side signature tools. If your settings look locked or your signature keeps getting replaced, ask your IT admin before changing anything.

Quick tips for a signature that holds up

• Make two versions. A full signature for new messages and a one-line version for replies keeps long threads readable.
• Keep images small and inline. Large or oddly embedded images are the usual reason signatures break or turn into attachments.
• Test it. Send a message to yourself and to an outside address (and open it on your phone) to see how it renders for recipients.
• Set it per account. If you have several mailboxes connected, each one has its own default signature setting.

Microsoft updates Outlook frequently, so specific labels and menus may change after October 2026. The underlying pattern of Settings, then Signatures, then choosing defaults has stayed consistent across versions.