Documents in a business transaction

Purchase order - To order goods

Delivery note - comes with order to verify it has arrived

Goods received notes - To check everything ordered is there and is in good condition.

Invoice - To get money for the goods sold.

Credit note - To refund any damaged or non-recieved goods.

Remittance advice slips - to attach payment

Statement of account - a summary of invoices

Payment - customer pays

Receipts - confirmation of payment