any easy code to pull user's email from mobile when using appts +

I wanted to know if anyone knew any easy code to make the appts+ pull the email from a users mobile instead of having them enter it in from their mobile.

I have seen this done on a ‘mobile’ landing page from friend’s website. It was coded so that just a button needed to be clicked on the users mobile and it would fire off an email from the mobile users email account on the mobile device to a set email address.