Aoa brother.
You'l need NOC from bank. If you bought the car on your name, bank will only issue noc on your name. Then take the cars smart card, NOC to Islamabad. Visit is necessary. Ask for car transfer counter. Talk to an agent, they may charge you some money n help you through the process.
Then after the payment is done, documentation is done , you'l go for physical inspection of car. Physically taking the car is necessary.
After physical inspection, you again submit the documents in excise office n get the slip for transfer.
Remember, taking the car is must, if you bought the car, bank will only issue noc on that's name. Then it will get transferred to that person. If someone else bought the car from bank, then first its transferred to his name , then again process repeated and transferred to your name.
NOC+smart card+any other documents+ CNIC of the buyer.