Keeping the right inventory is a challenge and when shoppers visit your store only to find out what they were looking for is out of stock, might affect your store. To save you and your customers from this inconvenience, you can use this feature to notify your user that the product they were looking for is back in stock and they can now own it. This will help you not lose the store engagement and sending out these emails will encourage people to come back.
For a user to receive such notification, all they have to do is subscribe to that product, and your role would be to enable "Notify Customer" feature, for this follow the below steps:
From platform background, Go to Your Apps -> Notify Customers