Set up an email signature in Outlook on the Web (Office 365)
1. Log in to your Outlook Web App at http://outlook.office.com/.
2. Next, click the gear icon at the top right corner of the screen and select Mail.
3. On the left pane, extend the Mail section, then the Layout section. Select Email signature.
4. To make you signature appear in every new email message, check the Automatically include my signature on new message I compose. Also, (optional) select Automatically include my signature on messages I forward or reply to. Then, compose your email signature using the available formatting tools.
5. Once your signature has been created, click Save so that all changes take effect.
That's it! Now you do not have to waste time on creating a signature every time you write a new email or send a reply.
If you want to change your email signature just follow the same steps above.