Formal.
According to relevant inquiries, Shuiyunjian K Song Muzu in Liupanshui has an online business license. Those with a business license are usually regular stores, so Shuiyunjian K Song Muzu in Liupanshui is formal.
A business license is a certificate issued by the industrial and commercial administration to industrial and commercial enterprises and individual traders allowing them to carry out certain production and commercial activities.