No objection letter require only in that case, if you wish to buy the car on your's company name i-e if the company is going to give you cash to go and buy the car on your own choice but under company's name. But if you are buying car for your personal use, only for your home and for other transporations purpose, no need any kind of letters. Just go to traffic department with the owner of car, fill the form, submit your copy of I.D and Insurance.