The specific requirements are as follows, according to IPWin, the main blogger in Zhihu.

The patent application submitted by 1.PCT can only be an application for a patent for invention or a patent for utility model, excluding an application for a patent for design.

2. Any national or resident who belongs to the PCT Contracting State has the right to file an international patent application. If there are multiple applicants in an international application, only one applicant can meet this requirement.