Invoice and credit sale

credit invoice.Sellers issue credit invoices for a variety of reasons. If a customer reports a problem with merchandise it purchased, the seller may issue a credit invoice. If the customer returns unused product, the seller may issue a credit invoice for the amount returned. If the customer is dissatisfied with a service provided, the seller may issue a credit invoice to the customer. A credit invoice reduces the amount of money the seller expects to receive from the customer. The seller reduces her accounts receivable for the amount of the credit invoice and increases sales returns and allowances. The buyer reduces his accounts payable for the amount of the credit invoice and reduces his inventory value.

Please tell me the documents that I shall give to the seller while making an inter state sale of goods . The sale is made on credit. Payment will be made with in 15 days.