You can add custom Email signatures to Emails sent from EarthLink WebMail. To create a new signature, login to https://webmail.earthlink.net/ and click on the Preferences option.
Then click on the Sending & Replying tab.
Click on Signatures.
Create a name for you signature in the Signature Name field and check the box next to Set as Default if you want this to be your default signature. The default signature will automatically be added to all outbound emails. Create your signature text in the box and click the Save button when you are done.
Once saved, you will see your new signature in the Signature List. You can click the Delete button to remove it or the Edit button to make changes.