What does it mean to have salary negotiable in a milk tea shop?

It means as follows:

Milk tea shop salary negotiation is a face-to-face negotiation between the applicant and the milk tea shop recruiter on salary, treatment, etc. based on personal abilities. Basic wage systems generally include: job skills wage system, position wage system, position grade wage system, job grade wage system, multiple structure wage system and salary point wage system, etc. This kind of salary system is imperfect and the salary is determined based on the person.

For companies with relatively standardized management, each position will have a fixed salary bandwidth range. If the recruitment notice of a milk tea shop simply states that salary is negotiable, it is very likely that the management of this milk tea shop is not standardized enough, the salary system is not sound, or there is no salary system at all. How much employees are paid depends entirely on the boss's preferences.