This is my 1st time visit to PRC. What document need for apply Visa?

The invitation letter from your supplier isn't enough. You should also ask your supplier to get an invitation letter from duly authorized Chinese unit, usually referring to local foreign affairs office. Besides, you should also provide covering letter from your company, in which the address, phone number and visiting purpose should be stated clearly. Your company's bank statement in recent 3 months (original one) is required. Lastly, a copy of your company's business registration certificate is needed.

Thank you very much