This is called the water cycle. Water falling from the atmosphere to earth is called precipitation. Water moving from the earth to the atmosphere is called evaporation. Rain is only one kind of precipitation. When rain occurs, some of it evaporates as it falls.
Evaporation also occurs when water vapor moves from the surface of the ground.
Much of the rainwater runs along the surface of the ground. This is called run-off water, and it moves from rivulet to stream to river. When the run-off water reaches a pond, lake, or ocean, evaporation constantly rises from the surfaces to these bodies of water. Rainwater also soaks into the ground. This is called groundwater.