From the left hand side, choose Mail -> Email Signature.To change your auto email signature in Office 365 webmail, please follow steps below: To change your auto email signature in Outlook 2010, please follow steps below: Now when you create a new email, replies or forward a email the signature you selected will be added in the email.On the right hand side, under the session Choose default signature, set the signature you preferred for New messages: and Replies/forwards:.Type your signatures in the Edit Signature text box.These signatures will automatically be added at the end of each mail you send. Provide a name for your signature then click OK In Outlook, you can add signatures to your emails easily.From the ribbon bar, choose File -> Options.To change your auto email signature in Outlook 2013/16, please follow steps below: