All receipts, including those of previous orders can be found on the Receipts screen, which can be accessed from the Profile screen. To see the details about a specific order, the customer can open an order receipt by tapping on it on the Receipt screen.
Keep in mind that the Customer will receive a confirmation email every time they make an order. Obviously with all the details of the order itself. This particular email includes an attached PDF with the order details and specifics ready to be easily printed, downloaded or forwarded.