Can we add graphic card to dell laptop d630

Are you trying to game on the laptop? I'm pretty sure you can't really add a graphics card outside the computer without the use of a ViDock, which wouldn't be worth it in your case.

If you are not gaming, you can add a graphics adapter to display the screen.

If your meaning something like putting a actual desktop graphics card in it no. Laptops do use different types of gpu's then what laptops use, therefor you would have to buy a whole new motherboard. Which would cost as much as whatever you bought the laptop for. If your interested in gaming I would just build a gaming computer on Newegg, tiger direct or any other place of that nature.