WordPress Version: 4.6
/**
* Initiates email notifications related to the creation of new users.
*
* Notifications are sent both to the site admin and to the newly created user.
*
* @since 4.4.0
* @since 4.6.0 Converted the `$notify` parameter to accept 'user' for sending
* notifications only to the user created.
*
* @param int $user_id ID of the newly created user.
* @param string $notify Optional. Type of notification that should happen. Accepts 'admin'
* or an empty string (admin only), 'user', or 'both' (admin and user).
* Default 'both'.
*/
function wp_send_new_user_notifications($user_id, $notify = 'both')
{
wp_new_user_notification($user_id, null, $notify);
}