How to move a cloud from one picture and insert it into another picture

I think the sky replacement Guided Edit first appeared in Elements 2021.  It has been improved in Elements 2023 and you can use the free trial to see for yourself.

However, in Elements 2020, you can use the Replace Background Guided Edit to replace the sky "background" with the sky from your own photo:

In the following gif, you will see the original photo, followed by a crude use of the Elements 2020 Replace Background Guided Edit, followed by the 2023 Perfect Landscape.  Elements 2023 has some stock skies to use.  In Elements 2020, you have to use your own sky replacement photo and I didn't spend any time looking for an appropriate example in this output.

One way I do it.  If I really need to add  cloud I simply use a cloud brush.

If I copy a cloud I just drop it into the new image and drag it around till the edges of the copied cloud (which generally will have some blue parts) blend in with the background.

What OS and version of Elements are you using?  Are you talking about moving a single cloud from one photo to another or replacing the entire sky e.g. a blue sky with a cloudy one?  If you insert the two photos into your post, we can have a better idea of what you want to do.  (And more recent versions of Elements will replace the sky automatically.)