waiting list email

hello In the product card (in the admin panel) the variable parameter is set. There is a tab (waiting list.) When the product is out of stock, you can enter your mail on the site and click add to the waiting list. Clients’ mails are added to this waiting list located in the admin panel. How can I make sure that when a client adds his mail, a notification is sent to the mail? Is there a hook in function.php or something else?