The movement of water on the earth's surface and through the atmosphere is known as the hydrologic cycle. Water is taken from the earth's surface in vapor form through evaporation. It is then moved from place to place by the wind until it is condensed back to its liquid phase to form clouds. Water then returns to the surface of the earth in the form of either liquid (rain) or solid (snow, sleet, etc.) precipitation. Water transport can also take place on or below the earth's surface by flowing glaciers, rivers, and groundwater flow.

This is well illustrated at the educational web site of the USGS.

The quantities of water involved in each of the stages of the cycle are enormous. Unfortunately, for human purposes, the largest fraction (97%) is salt water in the oceans and seas of the world.

Although it sounds like a small fraction, the other 3%, as discussed in the other pages of this web site, still represent a huge amount of water. Even this is still not all available for use. There is the frozen water in polar icecaps and galciers, and a great deal of groundwater in the earths aquifers, so most of us end up getting our water from surface sources.