Please find below code to send any documnet, PDF send through mail

/* Gravity forms */
function wdm_add_attachment( $notification, $form, $entry ) {
$upload_dir = wp_upload_dir();
if($form_id==9){
$notification[“attachments”] = $upload_dir[‘basedir’].’/pdf/order_new.pdf’;
}
return $notification;
}

add_filter(“gform_notification”, “wdm_add_attachment”, 9, 3);