The email tag is both a single tag and a container tag. Textpattern will replace it with a mailto: email link, according to the attributes set.
attributes
email=“unset”
linktext="Contact"
title="unset"
genealogy
Version 4.0.5
Simple e-mail link
<txp:email email="john.doe@example.com" linktext="Contact me" title="Send me an Email" />
Pre-populate message subject and body
<txp:email email="john.doe@example.com?subject=Lorem Ipsum&body=Sit amend" />
Container example
<txp:email email="foo@example.com" title="Email us!"><img src="/images/email.gif" /></txp:email>