PSB - Public Security Bureau
This is what the official invitation document looks like, stamped by the
Ministry of Foreign Affairs.
Bringing Family?
This document should contain all your
family members traveling with you for study,
work and Residing abroad in China.
Bringing a spouse or child? You will need
authentication services.

This is a sample document. Your document should resemble this
one in form and look but not in content which is unique to each
persons invitation.