I am offered a job in China so I need Z visa , can you tell me what documents are required ?

Hi, you should provide Foreign Expert Certificate issued by the State Foreign Expert Bureau and an invitation letter from China for work Z application. Other basic ones are your passport, application forms, physical check certificate and photo.

Thanks so Much Dear Billy
The chinese company needs to ask how to do an invitation letter for me

seems the first time they do you

can you know how and what they should write in it

Regards

The letter should be issued by the Foreign Affairs Office of the province (autonomous region, city) the company is located. So, just ask them to visit their local foreign affair office for that.