For example, if a company has a board of directors, who is the legal person and chairman of the company? General manager? What is the qualification of the general manager? Legal person or agent?

Of course, the general manager is the agent.

3. The project manager does not have the qualification of a legal person, so he needs the authorization of a legal person in more project applications or project handling. At the same time, at the time of the accident, he can't be the defendant, because he doesn't have legal personality.