The difference in price when buying clothes by scanning the QR code is a merchant problem. Merchants do not have a unified selling price on the system. A trademark is a sign used to identify and distinguish the source of goods or services. Any mark that can distinguish the goods of a natural person, legal person or other organization from the goods of others, including words, graphics, letters, numbers, three-dimensional signs, color combinations and sounds, etc., as well as combinations of the above elements, can be applied for registration as a trademark .