To transfer ownership of a vehicle to sell, applicants need to submit an application form, along with photocopies of CNICs for both the buyer and seller, a filled and signed Form 'F', a computerized transfer letter, and a transfer of ownership form. If the registered owner cannot appear in person, documents must be attested by a Class-I officer. For vehicles registered in other districts, proof of residence in Islamabad, photocopies of the registration book and complete vehicle registration file, and an NOC from the relevant Excise & Taxation Department are required. Additionally, an affidavit confirming the vehicle's legal status must be provided.