Go to Menu > Edit Menu
Select the menu where you'd like to mark a product as out of stock and click on “Edit menu”.
Select the item and disable it. Repeat the process for any other items you'd like to edit.
You can choose if you want the out of stock items to show on the menu or not.
You can also add stock quantities so items are automatically disabled from the menu once sold out.
Don't forget to press Save to apply the changes.