Changing Yahoo Mail Signature is not rocket science. You can do it easily if you know the right steps! To know how to change Yahoo Mail Signature, follow these steps. First, log in to your Yahoo Mail account and then go to the Settings menu icon. Next, scroll down and click on More Settings. After that, tap on the Writing email, and then you can click the Toggle button to either enable or disable your Yahoo Mail Signature. Now, enter or edit the signature in the given text box and save the changes.