How can I move pictures in iCloud photos to another folder?

You can do it in two ways... click on the iCloud app twice, so it would open two windows. Then use one window to select the pics... then on the second opened iCloud window... click on the folder you want to move the pics to, open that folder.... now go back to other window... select pic, the right click, scroll to copy and then go back to the second window. Then paste them in that new folder.

or second way... with both windows open of the folders.... as needed by following above instructions, drag pics and drop.