The point of sale (POS) or point of purchase (POP) is the time and place where a retail transaction is completed. It is the point at which a customer makes a payment to the merchant in exchange for goods or after provision of a service. At the point of sale, the merchant would prepare an invoice for the customer (which may be a cash register printout) or otherwise calculate the amount owed by the customer and provide options for the customer to make payment. After receiving payment, the merchant will also normally issue a receipt for the transaction. Usually the receipt is printed, but it is increasingly being dispensed electronically.