What are the requirements for a Z Visa for a US citizen?

The required application documents include:
1. Original signed passport with at least six months of remaining validity and blank pages, and a copy of the passport's data page and the photo page if it is separate.
2. One completed Application Form with a recently-taken color passport photo (bare-head, full face) against a light background attached
3. Foreigners Work Permit of the People's Republic of China issued by Chinese government authorities for Human Resources and Social Security, as well as Invitation Letter of Duly Authorized Entity or Confirmation Letter of Invitation issued by relevant Chinese entities; if your intended work period is 90 days or less, you need to provide an Approval of Short-Term Employment for Foreigners Working in P.R. China.