I'm trying to understand does putting something in iCloud drive automatically download it on another mac or does it show up with down arrow to download if the user wants to.
It works exactly the same way Dropbox / GDrive / Copy / OneDrive / anyother. You put files on it, they sync to all devices.
That being said, they may include a selective sync feature as many of these do that would allow you to manually exclude particular folders syncing on particular devices.
Its interesting that when I add something into iCloud drive using the browser, I get the download icon next to the file in finder but the download starts automatically.
Its interesting that when I add something into iCloud drive using the browser, I get the download icon next to the file in finder but the download starts automatically.