Button on user profile page to send email
To get what you want, you need to modify the template user, to do this you need to follow the next steps:


Find the file called user-profile.tpl it is in the module user modules\user (NOT inside sites/all/modules).
Once you found it, open it, and you should see at the end of the file something like this:



  print render($user_profile);



Now copy and paste this line of code inside php tags: 



  $usr = user_load(arg(1));
  
  echo 'mail.'?Subject=textyouwant"
  target="_blank">Send Mail';


That should work !