A graphics card is a card that you need to play games especially 3D games such as GTA(Grand Theft Auto) series games, Need For Speed, etc. There are brands such as NVIDIA, Powercolor and Gigabyte producing good-quality graphics cards.
A graphics card has a VGA port which is mostly blue in colour. You connect the monitor to this port through the VGA cable included with your monitor whose ends are also blue in colour. It is this port through which the graphics card outputs the processed graphics to the monitor.
Another part is the GPU or the Graphical Processing Unit where all the graphics are processed to feed to the VGA port and to the Monitor. Most graphics cards have a fan that cools the CPU otherwise it may function abnormally. Then is the Graphics Memory. The more memory you have, games function better. It can be 256 MB, 512 MB and 1204 MB(1 GB) . The cheapest available graphics card is found on Flipkart at the rate of Rs. 1937. So, the final verdict is that if you play demanding game, then use a video card.