Water vapor is the gas state of water whereas moisture is the liquid state of water. When water evaporates, it goes from liquid to gas. The main difference between these two states is that moisture is a liquid and water vapor is a gas.
When water evaporates, it absorbs heat from its surroundings. This process is called latent heat of vaporization and it’s what makes sweating such an effective way to cool down on a hot day. The heat energy needed to convert 1 gram of water into vapor at body temperature (37°C) is about 2,500 joules—or about 600 calories. (This explains why you can lose weight by sweating!)
Water vapor in the atmosphere comes from evaporation at the Earth’s surface—from oceans, lakes, rivers, wet soil, and plants. Plants release water vapor through their leaves via a process called transpiration. Animals also release water vapor when they exhale air from their lungs during respiration.