What documents do I need to provide for one year multi entry visa?

Anastasiia, you should apply for a work type to enter PRC and work there. The required documents include your passport and copy of its data page, the application form attached with a passport-style photo, an invitation letter of a duly authorized unit, and the alien employment permit (the company will get the last two documents for you). And then submit your application to the embassy of PRC to apply for it. After you enter PRC, you can apply for a temporary residence permit which will allow you to work there for a year.