Modify the admin notification sent out when new users signup

gistfile1.php

<?php
function pw_rcp_custom_email_notice( $message, $user_id ) {
	
	$user_data = get_userdata( $user_id );
	$user_email = $user_data->user_email;

	$message = "Hello admin, this is a custom alert message!\n\n";
	$message .= "$user_email just signed up for an account.";

	return $message;

}
add_filter( 'rcp_before_admin_email_active_thanks', 'pw_rcp_custom_email_notice', 10, 2 );