An invoice is a formal document issued by a seller to a buyer, detailing the products or services provided, their corresponding quantities and prices, and the total amount due for payment. It serves as a transaction record and a request for payment. Invoices include essential information such as the seller's and buyer's contact details, itemized descriptions, payment terms, and any applicable taxes or discounts. Proper and timely invoicing is crucial for maintaining transparent financial transactions, managing cash flow, and facilitating smooth business operations in the retail sector.