Couriers and messengers receive their instructions either in person—by reporting to their office—or by telephone, two-way radio, or wireless data service. Then they pick up the item and carry it to its destination. After each pickup or delivery, they check in with their dispatcher to receive instructions. Sometimes the dispatcher will contact them while they are between stops, and they may be routed to go past a stop that recently called in a delivery. Because most couriers and messengers work on commission, they are carrying more than one package at any given time of the day. Consequently, most couriers and messengers spend much of their time outdoors or in their vehicle. They usually maintain records of deliveries and often obtain signatures from the persons receiving the items.

Most couriers and messengers deliver items within a limited geographic area, such as a city or metropolitan area. Items that need to go longer distances usually are sent by mail or by an overnight delivery service. Some couriers and messengers carry items only for their employer, which typically might be a law firm, bank, or financial institution. Others may act as part of an organization's internal mail system and carry items mainly within the organization's buildings or entirely within one building. Many couriers and messengers work for messenger or courier services; for a fee, they pick up items from anyone and deliver them to specified destinations within a local area. Most are paid on a commission basis.

Couriers and messengers reach their destination by several methods. Many drive vans or cars or ride motorcycles. A few travel by foot, especially in urban areas or when making deliveries nearby. In congested urban areas, messengers often use bicycles to make deliveries. Bicycle messengers usually are employed by messenger or courier services. Although e-mail and fax machines can deliver information faster than couriers and messengers can, and although a great deal of information is available over the Internet, an electronic copy cannot substitute for the original document in many types of business transactions.