requirements for chinese working visa. indian passport holder. im present in china as a trainee.

Shanmukh, if you have found a job, you can ask your employer to get work permit and invitation letter from duly authorized unit for you. Only when you get the two things and prepare other relevant documents can you apply for work Z type. Other relevant documents include your passport and its copy, a recent color photo, and the application form. But I’m afraid you need to exit and apply for it in your country.
By the way, can I know what type of entry permit you hold now? Maybe it’s possible to change the current type to Z type.