Yes, you can create HTML rich email signatures
(iMore iPhone)

Add some flair to your email signature on iPhone with rich text. Sending emails from the Mail app is fast and easy, but sometimes you need more than plain text to make your messages stand out. In those cases, you might want to add a little bit more expression and create rich HTML signatures on iPhone and iPad to shake things up a little. With this form of text, you can include imagery and dynamic HTML content to your signature. Here`s how to do it. How to create rich HTML signatures on iPhone and iPad Although Mail on iOS can display rich HTML email messages, you can`t do much more than add bold, italics, and underlines to message text. There is a way to create rich HTML signatures on iPhone or your iPad, however. You can use any app that can create rich HTML text, but probably the easiest way to do this is to use the rich text signature from the email app on your Mac or Windows PC. Send yourself an email that includes your rich HTML signature. On your iPhone or iPad, tap the...