What is the primary purpose of an invoice?

The primary purpose of an invoice is to serve as a detailed statement that outlines the goods or services provided, along with the amount due for payment. Invoices are crucial for record-keeping on both the buyer’s and seller’s sides. They not only specify what has been sold but also include essential details such as quantities, prices, and terms of payment, which help facilitate the transaction. By providing a comprehensive account of the items delivered and their associated costs, invoices enable both parties to verify the transaction's accuracy, ensuring that the seller receives payment for the goods or services rendered.

While summaries of returns and exchanges, inventory lists, and contracts do play important roles in the overall operations and logistics of transportation and trading, they do not encapsulate the primary function of an invoice, which is focused specifically on billing for sold goods or services.