If I want to go to work to Hong Kong, wath kind of VISA I require?

You can try to apply for the Employment as Professionals' one.
You need to prepare the documents as followed for applying: application for Entry for Employment as Professionals in HK with recent photo, your travel documents such as your passport or other documents containing your personal particulars, date of issue etc, transcript of academic records, academic qualifications and working experience. Then you can apply through your documents to the Chinese embassy in your country or deliver all of them to HK Immigration Department for applying.