<!-- link with a single email address -->
<a href="mailto:john@doe.com">Click here to send us an email</a>
<!-- link with an email address, and a CC email address -->
<a href="mailto:john@doe.com?cc=jane@doe.com">Click here to send us an email</a>
<!-- link with an email address, a CC email address, and a subject line -->
<!-- keep in mind that the subject line should be "URL encoded" :) -->
<a href="mailto:john@doe.com?cc=jane@doe.com&subject=I%20would%20like%20to%20get%20in%20touch">Click here to send us an email</a>
<!-- I hope that this helps, happy coding <3 -->