An invoice for progress payment is a document used by businesses to request payment for work done to date. It typically includes the business name, details of services rendered, and amount due as determined from an agreed price or rate. The invoice also usually includes a payment deadline, after which additional interest or late fees may be charged. This type of invoice is especially important when working with clients and vendors on ongoing projects or services, where regular payments must be made as each stage or milestone of the project is reached. In effect, these invoices serve as both a billing record and a progress report for the project, keeping all parties involved accountable for their responsibilities.