How to create/edit EMail Signature
Here you will find information on how to create your signature and choose when Outlook adds a signature to your messages.
1- Sign in to Outlook on the web.
https://outlook.office365.com/mail/
2- Go to Settings
3- On the next window, choose Account and open Signature.
4- Under Email signature, type your signature and use the available formatting options to change its appearance. Then, choose Save. Note: You can have only one signature per account.