Couriers vary in size and shape depending on their preferences. Furthermore, there is always room for quality improvement. As a result, some services may even provide better services than others. It is critical to understand that there are no such things as standard goods that are delivered by every company. Each one has something special added to it that changes over time. Express couriers, parcel couriers, domestic couriers, international couriers, mailbox couriers, delivery men, e-parcel couriers, DHL, UPS couriers, TNT, USPS couriers, DHL overseas agents, Canada Post customer care centers, and so on are some of the common services provided by couriers.