When customers pay their bills, the person in charge receive copies of the payment receipt vouchers. Payment vouchers are documents show that money was received from customers for invoices. They show that the payment was received. The records of payment receipt vouchers are called customer payment histories. By looking at the customer payment history records, the person in charge of sale knows if customers pay their bills on time. Each customer has a credit limit. The credit limit is the most that customer can owe and still buy from the company. If a customer owes more than the limit, the salesman cannot approve an order. However, the credit manager can approve the order if he thinks the customer will pay. Often the credit manager will call the customer and ask for some payment before the order is shipped or dispatched.