Water vapor is an invisible gas, so you can't see it. Clouds form when water vapor in the air condenses into liquid water or ice crystals. This happens when the air temperature drops below the dew point, which is the temperature at which the air can no longer hold all of the water vapor that it contains.
The type of cloud that forms depends on the temperature and humidity of the air. If the air is cold enough, the water vapor will condense into ice crystals, forming ice clouds. If the air is warmer, the water vapor will condense into liquid water droplets, forming water clouds.
