To Change Email Signature in Outlook, open Outlook and then click "New Email" to create a blank email message. In the untitled email message, you need to go to the ribbon bar and click "Signature" and then "Signatures" In the "Select signatures to edit" window at the top left, choose the signature you want to change. In the "edit signature" window, make the changes to the signature. You can edit the text as well as change the formatting or add elements like images. When you're done, click "OK." and save the changes.