We called that feature "parking" the invoice. It's pretty standard on every good POS system. It can also become a challenge if you have a lot of those and want

We called that feature "parking" the invoice. It's pretty standard on every good POS system. It can also become a challenge if you have a lot of those and want to find the right one. We had some users that prepared a lot of orders in advance into bags, so they can hand them to the customers right away when they come. Best solution was to print a delivery note for every order, attach them to the bag and then scan a barcode on the bag when the customer comes for pick up/payment. And you also need to be able to add or remove items before the customer pays, people often change their mind.