Water moves from the ground or oceans into the atmosphere through a process called evaporation. It's a process that happens on a molecular level when the molecules of water are really energized and rise into the air.
Water evaporates from the surface of the sea into the air. The water vapors condensed in the air and take the shape of clouds. And when the water vapors become heavier than air its starts raining. This is how the ocean water turns into rain and the cycle goes on.