stay in Beijing for 3 months what kind of visa do I need and what's requirements to get it

Thal, may I know what your purpose is to stay in Beijing? If you go there for tourism purpose, I’m afraid you cannot get a tourist L type with stay duration of 3 months. In most cases, you can only get a L type with stay duration of 30 days. But you can apply for an extension 7 days earlier before it expires. In this way, you can get another 30 days.
The required documents for tourist L type include the application form, a recently-taken passport-sized color photo, hotel reservation, your passport and its copy, as well as flight itinerary.