By default, MainWP will use Administration Email Address that you have saved on the WP Admin > General Settings page for most email notifications.

However, the FROM address for MainWP can be adjusted using a filter without affecting the Administration Email Address.

To do so,

1. Install MainWP Custom Dashboard extension
2. Navigate to your MainWP Dashboard > Extensions > Custom Dashboard
3. Open PHP tab
4. Add the following code snippet

   add_filter( 'mainwp_send_mail_from_header', 'myhook_mainwp_send_mail_from_header', 10, 3 );
   function myhook_mainwp_send_mail_from_header( $input, $email, $subject ) {
   	 return array(
   	 'from_name' => 'custom-from-name',
   	 'from_email' => 'custom-from-email',		 
   	 );
   }

5. Click the Save Changes button

If you wish to change the FROM address only for specific emails that are being sent by MainWP (e.g. Daily Digest emails), you can use a variation of the above code snippet:

add_filter( 'mainwp_send_mail_from_header', 'myhook_mainwp_send_mail_from_header', 10, 3 );
function myhook_mainwp_send_mail_from_header( $input, $email, $subject ) {
	if ( 'some-email' == $email &&  'some-subject' == $subject ) {
	 return array(
	 'from_name' => 'custom-from-name',
	 'from_email' => 'custom-from-email',		 
	 ); 
	}
	return $input;
}