Yeah, unless I don’t understand your question, it’s super easy to do.
Just find yourself a bunch of cloud png images ( a bundle in which they all are more or less the same color grading is better) and import them as images on planes (use the addon for this).
Scale, overlap and place them where you want.
You can even subdivide the planes and sculpt them in the shape you think the cloud has. This way they’ll catch light differently.
You can play with the shadow’s transparency to have the casted shadows more or less intense.
Let me know if that answer your question.