The couriers mentioned when buying things online include ZTO, STO and EMC. They represent different courier companies. Generally, buyers can specify the courier company according to their own needs, and it is EMS and not EMC. .\x0d\ZTO refers to ZTO Express. \x0d\ Zhongtong Express Co., Ltd. was founded on May 8, 2002. It is a domestic logistics and express company integrating express delivery, logistics, e-commerce, and printing. Registered trademarks "ZTO" and "ZTO". The current chairman is Lai Meisong. \x0d\STO refers to STO Express. \x0d\Shanghai STO Logistics Company has 247 independent city business offices, 179 business halls, and 1,220 operation points. Express was founded in 1993 and is a domestic joint venture (private) enterprise mainly engaged in express delivery. It basically covers cities at or above the prefecture level across the country and cities at or above the county level in developed areas, especially in Jiangsu, Zhejiang and Shanghai, basically achieving no blind spots in delivery. In February 2014, STO began internal testing of overseas shopping transshipment business. \x0d\EMS is worth postal express. \x0d\EMS (ie "ExpressMailService"), express postal service. It is an international mail express service managed by the Universal Postal Union and an express service provided by China Post. This business enjoys priority processing rights in customs, aviation and other departments. It delivers various documents and items such as international and domestic emergency letters, documents, financial bills, and commodity samples to users with high quality.