mail.php

$email = new PHPMailer();
$email->From      = '[email protected]';
$email->FromName  = 'Your Name';
$email->Subject   = 'Message Subject';
$email->Body      = $bodytext;
$email->AddAddress( '[email protected]' );

$file_to_attach = 'PATH_OF_YOUR_FILE_HERE';

$email->AddAttachment( $file_to_attach , 'NameOfFile.pdf' );

return $email->Send();