Does 1&1 webmail support HTML signatures?
No — 1&1's webmail client doesn't support HTML signatures at this time.
How do I use my htmlsig signature with a 1&1 email account?
Connect your 1&1 email account to a desktop or third-party email client instead, and install your signature there. We recommend:
Gmail (by connecting your 1&1 account to Gmail via IMAP)
