How can a Pakistani citizen get a work visa for Macau?

You can apply through Chinese embassy. For purpose of work, following documents are required:
1. A completed application form; [The form is available at the respective Subdivision and the website of the Macao PSP.]
2. Copy of the bio data page of a valid passport/travel document;
3. Copy of employment approval document issued by the Macao authorities (i.e. the application or renewal application of "Authorization to Stay for Non-resident Workers" which has been verified by the Macao Immigration Department).
Fee is USD30, extra USD 20 is required as communication fee of relating to the Macao Immigration Department.

Hey thanks for your very helpful reply.

But I don't know how to get the application of "Authorization to Stay for Non-resident Workers" verified by the Macao Immigration Department.

Can you kindly advise me what should I do to get this employment approval document. I don't have any relative living there or anyone who could offer me with a job.

Sorry, you should start with a job offer first so that your future employer will help you with this.