This article explains how to set up an email signature in Mail for Windows 10. The instructions apply to the Mail app for Windows 10 only.
How to Add an Email Signature to the Mail App in Windows 10, 11
If you have more than one email account set up in Mail for Windows, create a separate signature for each account or use the same signature for all your accounts.
To change the default signature added to emails:
Open Mail for Windows.
