Manufacturer code or brand code. According to the query of Wukong Finance and Taxation, the letter in front of cf gold represents the manufacturer code, and cf represents the manufacturer code or brand code. Invoice refers to the business vouchers issued and collected by all units and individuals in buying and selling goods, providing or receiving services and engaging in other business activities. It is the original basis of accounting, and it is also an important basis for law enforcement inspection by audit institutions and tax authorities.