Change format of webform emails via hook
The hook you are looking for is hook_mail_alter.

To modify webform submissions emails your code should look like:

function MYMODULE_mail_alter(&amp;$message){
  if ($message['module'] == 'webform' &amp;&amp; $message['key' == 'submission']){
    /*** Place your code here ***/
  }
}


This will alter just the webform submissions emails.