Ghee is a type of clarified butter that's typically made from cow's milk.
Ghee can be used in the same way that you'd use butter or most types of oil. You can warm it in a pan/boil and use it to soute your favorite vegetables. You can also melt it down and use it for baking to replace the same amount of melt butter or oil.
Ghee can also be used as a spread, just like butter or margarine. Basically, you can use it for anything but, like butter, any home cook should be mindful of its macro profile before overindulging.