Igneous rock forms by lava. Once it cools, it forms this type of rock. However, igneous rock can also form on a volcano. If the lava cools fast, the rock will be smooth. If it cools slow, the rock will be rough and not smooth.
Sedimentary rock is formed within Earth's bodies of water. This rock can be transported by wind, water, or ice. But before getting transported, the rock has to get weathered. Sedimentary rock is used for houses, canals, and many other things.
The word " Metamorphic " means to change form. So it's pretty obvious that metamorphic rock does this event. The original metamorphic rock is called Protolith. Did you know that metamorphic rock can be igneous or sedimentary rock that is really old?