It is the action of issuing a bill when buying and selling goods or services. It is also known as invoicing.

A bill is a document that includes all the information related to a purchase-sale operation of a good or service and it is also used as a proof or purchase-sale. The term billing refers to the seller handing over these bills and the buyer taking them. The department of a company in charge of preparing and sending out billings is the invoicing department.