The employment certificate cannot be issued or signed by a witness. The unit employment certificate requires my signature. Only my signature can be valid. After my signature, it needs to be included in my personal file information. The employment certificate is the work certificate. The work certificate refers to a certification document for Chinese citizens in daily production, life and business activities. It is generally used for professional title evaluation, qualification examination, work income certificate, etc. It needs to be issued by the work unit and stamped with the company's official seal to be valid.