Foundation is the basis of the make-up and should be chosen carefully.
It is best to choose a color as close as possible to the natural color of the skin in normal daylight. What kind of foundation you choose depends on the purpose for which you use it.
Do you want to create the most natural look, with makeup may stand out as little as possible, then choose a nearly transparent foundation. The effect that you attain this, is also called the nude-effect. It seems as if the skin is naturally perfect.
Do you need a foundation that provides an even tone and lets you easily eliminates spots, then choose a foundation with an opaque texture.