A Purchase Order is a document between a supplier and a buyer that confirms a purchase. It details the items the buyer agrees to purchase at a certain price. It also outlines the delivery date and terms of payment for the buyer. Purchase Orders make the purchasing process more efficient and allow for better inventory and payment tracking.
An Invoice is a document issued by a seller to a buyer. It identifies the seller and the buyer, the items sold, the quantities, the prices, any discounts, and delivery and payment terms. An Invoice also serves as a demand for payment and hence helps a healthy cash flow.