Mailto snippet with subject and body text and styled link:

<a href="mailto:((Email))?subject=A Subject&body=A Body" target="_blank" style="color:#000001;text-decoration: none;">
  <span style="color:#000001">
    ((Email))
  </span>
</a>


How to choose Outlook 2016 to open when mailto: is clicked:


How Outlook 2016 open when email link is clicked: