- Log in to your Outlook on the Web account and go to the Mail app.
- Then, go to the settings (it’s a gear icon at the top right-corner of the screen) and click Mail(Office 365).
3. On the left pane, extend the Mail section, then Layout and select Email signature.
4. To make signature appearing in every new email message, check the Automatically include my signature on new messages I compose box.
5. Once your signature has been created, hit the Save button so that all changes take effect.