A document issued by the seller's own courier and signed by the customer to acknowledge receipt of the goods is

The document you are referring to is a Delivery Note. A Delivery Note is a document that confirms that goods have been received by the customer from the seller. It is issued by the seller's own courier and signed by the customer as proof of receipt. The Delivery Note contains details about the goods, such as the quantity, type, and description, as well as the date and location of delivery. This document is important for both the seller and the customer as it serves as a record of the transaction and helps to ensure that the goods were delivered as expected. In the event of a dispute, the Delivery Note can be used as evidence to support either party's claim.