documents required for Business M Visa

You need to provide your passport and its photocopy, the filled-out application form, a recently-taken half-length color photo, Invitation Letter of Duly Authorized Unit, an invitation letter from your business partner, local company covering letter, recent 3-month bank statement, and copy of Business Registration Certificate of your company.
Government Approval Letter or Invitation Letter of Duly Authorized Unit is a pre-approval document issued by a Chinese Government agency. You will need an inviting company in China to obtain that for you.