i have been driving for 3 years and i dont have license and i dont keep documents of car with me anytime.
i dont know about islamabad but in karachi you dont need any license, just keep some money and everything is done for you.
just worry about the road sense, you are new to the system and people's driving habits in pakistan.
i can remember once my friend said
"when driving a car, only you have eyes all others are blind. When riding a bike, you are blind others will take care of you"

take care