If you have an @Yahoo, @AOL, @SBCGlobal or @BellSouth email address, you may be eligible to use Yahoo Stationery - a set of templates that allow you to include one of over 50 designs as the background for any personal email you send from an eligible account. Please note that at this time Stationery is not available for all Yahoo or AT&T-based accounts.
Yahoo Stationery is a product that is separate from Paperless Post, and is therefore supported by Yahoo or AT&T.
If you'd like to add or remove Stationery from your emails, you find some use instructions here for Yahoo domains and here for AT&T (SBCGlobal and BellSouth) domains.
If you have any additional questions about the Stationery product, please reach out to your email provider's support team or check out Yahoo's Help Center or AT&T's Help Center.