I wanna visit a friend in different cities of China, what other requirements should i secure?

You need to prepare your valid passport and a photocopy of its data page, a completed application form glued with your recently taken color photo, and an invitation letter from your friend. If you come to China for the first time, you should also provide proofs about your financial standing, employment, or study, such as bank statement in the latest six months and the receipt issued by the bank for providing the certificate, BIR-stamped income tax return form, salary and work length certificate issued by your employer, professional ID, etc.