Foundation is the base for any make up. It defines the features of the face and hence it is very important in your make up. There are many tones and shades in the skin. Similarly there are foundations that suit each shade of skin.
Before buying a particular foundation one has to make sure that the foundation is suitable for their skin. There are many simple methods by which one can know the foundation which would suit you.
There are many brands that come up with foundations, and not all shades are available in all brands. Hence it is best to check the shade of foundation each time you buy.