A courier is a business that handles package delivery. Couriers can deliver all types of items. Independent couriers often deliver things like documents, parcels, and letters for business. Couriers who work with retail partners may deliver things from retailers, such as Amazon, or for large transportation companies, such as FedEx. While people think of couriers as the people who deliver things to them, a courier service actually handles the logistics from getting the item from one point to another.