Warm greeting. Hi its me nepali citizen working in qatar.

Bijaya, first, you should provide copy of passport, a filled-out application form, a recently-taken passport-style photo, proof of financial support, transportation and accommodation arrangement, and your travel plan.
And then post the application to HK immigration department. Below is the postal address:
Receipt and Despatch Sub-unit
HK Immigration Department
2/F, Immigration Tower
7 Gloucester Road
Wan Chai, HK