You need to prepare the below documents for C visa application:
(i) Original passport which has more than 6 months left before it expires from the date of application and sufficient blank visa pages.

(ii) One completed Visa Application Form with a recently-taken passport photo (only color photo with light background like light blue and white is acceptable);

(iii) Related certificate(s) as provided for in the bilateral agreement or as required by the Chinese side, such as an official letter issued by their companies or corporations stating that they apply for a crew visa. Crew members of foreign airways who perform duties on international flight operated by Chinese carriers under an exchange program should provide invitation letter issued by an authorized unit in China (original).