i am pakistani? i want to get z visa in china

If you want to get a Z type, you need to find a job in China. After you got a job in China, your employer will issue you an invitation letter and a work permit. With these two documents and some other basic documents, you can apply for a Work Z for China. BTW, applying in China is not possible, so you need to go to another country for applying.

If you just want to start a business, you cannot get a Work Z, personally speaking, but you can try to apply for a M type.