hi, i am Ahmed from pakistan and doing studies in guangzhou.

You can apply for it.
The first step is to prepare these materials: copy of your passport, proof of your financial support, hotel reservation, transportation arrangement, a completed application form, a passport-style photo, and your travel itinerary.
The next step is to post your application to HK immigration department to apply. Here is the postal address:
Receipt and Despatch Sub-unit
HK Immigration Department
2/F, Immigration Tower
7 Gloucester Road
Wan Chai, HK