Invoices should have dates to clarify obligations for both the issuer and recipient. The invoice date is the date of the document's issue -- not necessarily the date the products or services were provided. Terms of payment are interpreted in relation to this date. The date is also one way individual invoices are recorded and distinguished from one another. Invoice dates should be displayed prominently to prevent confusion over the invoice and to ensure the invoice is a reliable document.
Invoices include a timeline for shipment of goods or expectation of payment. The payment term of "net 30 days," for example, is calculated from the invoice date, so that the payment is due no later than 30 days from the date of the invoice. The shipment date may be the date of the invoice if the invoice was produced the same day the goods were shipped. If a payment becomes overdue, businesses will rely on the timeline provided by the invoice date and the terms to take collection activity. If customers receive a discount for early payment, these dates determine whether the invoice was paid in sufficient time to receive the bonus.
Businesses that send out a lot of invoices should have a system to generate unique invoice numbers for each sale. A sequential numbering system ensures that invoices are easily tracked when they are produced and paid, even if several invoices are produced with the same invoice date.