Clouds are entirely made up of tiny droplets of water. In fact, the droplets or ice crystals are so small, they do not fall through the atmosphere, because to them the atmosphere feels as thick (viscous) as we would feel in syrup. That's how clouds are able to stay up in the air. Clouds absorb water from evaporation of the water on the ground. The water that evaporates forms these droplets in the upper atmosphere.

Clouds are made of tiny drops of water (or crystals of ice). Water vapor (gas) in the air condenses to form a liquid or solid when the air is too cold to hold the water in it. On the ground, this causes dew (liquid) or rime (ice), but in the air, without anything to condense onto, the water forms clouds of droplets or ice crystals. If these droplets or crystals get big enough that the wind can't hold them up anymore, they fall to the ground as rain or as snow.