Any student can apply against Open merit seats, who fulfills the requirements. Some institutions have distributed these seats on districts and region basis, which is determined by domicile certificate. It may vary slightly from institution to institution. Open merit fee in Public sector should be nominal but some of the institutions have increased the amount due to financial constraints and it still does not exceed from the range of common man.
All seats other than open merit are called reserved seats. But the system of distribution, nomination, and the availing process can differ. There are about 25 different categories of reserved seats in Pakistan other than various schemes. e.g. Districts, Urban and Rural, Navy, Air Force, Local students Self Finance, Overseas Pakistanis, Foreign National student Self finance (Overseas having dual nationality can also apply against these seats), Disables, Hifaz-e-Qur'an, Sports, Teacher's Child, Alumni, Engineer's and Doctor's children, FATA, FANA, Azad Kashmir, Provinces, International seats for cordial relations ( under Pakistan Technical Assistance Program and Cultural Exchange Program), Female students, Federal Capital etc.