It's a very common and enthusiastic way to express agreement or affirmation.
Here are some examples:
* "¿Quieres ir al cine conmigo?" (Do you want to go to the movies with me?)
* "Claro que sí!" (Of course!)
* "¿Te gusta la pizza?" (Do you like pizza?)
* "Claro que sí, me encanta!" (Of course, I love it!)
You can use "Claro que sí" in many situations where you would say "yes" in English, but it carries a stronger sense of enthusiasm and certainty.