how can i apply for a visa for my friend who will be staying with me for approx 3 months?

Aditya, your friend can apply for a tourist L type to enter China. First, prepare those documents: passport and photocopy of its data page, a filled-out application form, a passport-style photo taken recently, and the invitation letter from you. Next, your friends should go to the CVASC to submit the application and apply for the tourist L type.