Question

Why clouds are fluffy​

Answer 1

Cumulus clouds form in rising air. The cloudy air becomes warmer than its surrounds and continues to rise as a buoyant thermal. These thermals transport the cloud droplets upwards; they grow from more condensation or from colliding with other drops

Answer 2

Clouds aren't physical to touch but they are "fluffy" from the cause of vaporized water and the gas and materials that made this "fluffy cloud" on the sky.