Studio lighting is used because the light can be easily manipulated and controlled to produce the desired image for a photographer.

Studio lighting can be continuous or flash. Continuous lighting is when there is always a source of light, like a base fro lighting. Flash lighting is a burst of light that helps to eliminate unwanted shadows.
Combinations of light can be used - flash and continuous and 1 2 and 3 point lighting.

1 2 and 3 point lighting is used to illuminate different parts of the subject that add other dimensions and moods to the photographs, but also to keep the photographs well lit. 

Fill lighting lights up the areas where there is shadow; fills the shadows formed by other lights with light.
Spill light is the light that falls where it is not intended to fall and creates shadows hence why fill lighting is used to prevent this.