what are the requirements or what should I prepared a documents to have a working visa in HK

Hi, you should prepare those documents including copy of passport, a completed application form, a recently-taken passport-style photo, work experience and schooling certificate, and copy of the alien employment permit. Your employer needs to provide the application form, copy of the contract, business certificate, copy of the financial support, and introduction letter of the company. Just for reference. You can check the official website of the HK entry and exit administration bureau for detailed information.

Thank you for the info. florrie, where can i get the application form? The allien employment permit?

You can try to find the application form from the official website of the China embassy in your country. You can ask your employer to provide you the alien employment permit.