You can apply for a Tourist Visa to China for visiting your friend, the requirements are:
1. Application form
2. Applicant's passport
3. One recent passport size photograph.
4. One Passport photocopy.
5. Covering letter from your company or employer addressed to the visa office.
6. Photocopy of a confirmed return air ticket
7. proof of travel expenses, first tourist applicant is required to provide 1.5 lacs.