Creating link to email address in HTML
Creating a link to an email address is almost identical to creating a link to a web page. But instead of the URL designate mailto: email address (example 1).
Example 1. Link to the e-mail address.
<a href="mailto:firstname.lastname@example.org">Ask your questions via e-mail</a>
Such a link is identical to the link to a web page, but if you click it, a default e-mail program will run. Therefore, for the user to know what will be run the name of the link should indicate that it's an e-mail.
You can also automatically add a subject message, by adding to the e-mail's address, with the help character question mark (?), parameter
subject="Subject" (example 2).
Example 2. Setting the subject.
<a href="mailto:email@example.com?subject=Question about HTML">Ask your questions via e-mail</a>
Now if you start the e-mail program the field Subject will be filled automatically.