To change your auto email signature in Outlook 2024/2019 (legacy layout), please follow steps below:

1. From the ribbon bar, choose File -> Options.
2. From the left panel, choose Mail.
3. Then click the Signatures... button.
   

To create signature:
• Click the New button.
• Provide a name for your signature then click OK
• Type your signatures in the Edit Signature text box.


• When done, click OK.

• Under the session Choose default signature, set the signature you preferred for New messages: and Replies/forwards:.
• Then click the OK button.
• Now when you create a new email, replies or forward a email the signature you selected will be added in the email.

To change your auto email signature in Microsoft 365 (M365 web app), please follow steps below: (For the Outlook (new) app, click "Settings (the gear icon) > Account > Signature" (please refer to the screen of step 3).

1. Login Microsoft 365 portal.
2. Go the Outlook Web app.
3. Click the gest icon from the top right hand corner.
4. Click "Account > Signature".
   

To create signature:
• Click "+New Signature".
• Enter a Signature name.
• Type your signatures in the text box.
• When done, click Save.

Set Auto Signature:
• From the "Select default signatures" session, set the signature you preferred for New messages: and Replies/forwards:.
• Then click the Save.
• Now when you create a new email, replies or forward a email the signature you selected will be added in the email.