Invoice 3 is an accounting document issued by a seller to a buyer that records the details of a sale, including the goods or services sold, the amount due and the payment terms. It is an important document for both parties involved in the transaction, as it serves as a record of the sale and provides proof of the buyer's obligation to pay for the goods or services received. There are two main types of Invoice 3: a proforma invoice and a sales invoice. A proforma invoice is issued prior to the sale and typically includes an estimated total for the goods or services provided. A sales invoice is issued after the sale has been completed and includes the actual amount due for the goods or services purchased.