The reason clouds are white and the sky is blue has to do with the size of the particles and the length of light wavelengths.
Air has small particles, so most of the sun’s light just passes straight through it.
However, blue light has a short wavelength, so some of it goes careening off the small particles and bounces around the air above you before reaching your eye.
As a result, the sun looks more orange on Earth than it looks in space, and the sky looks more blue.
In the case of clouds, the water mist adds larger particles to the mix, so that all colors, not just blue, are scattered in all directions.
All colors combined make the clouds look white.