You can also control those settings directly within each app. The button for each recommendation in the Storage Management window affects one or more settings in other apps.
iCloud storage starts at 50GB for $0.99 (USD) a month, and you can purchase additional storage directly from your Apple device. If you reach or exceed your iCloud storage limit, you can either buy more iCloud storage or make more iCloud storage available. Storing files in iCloud uses the storage space in your iCloud storage plan. When storage space is needed, only the messages and attachments you recently opened are kept on your Mac. Store all messages and attachments in iCloud. To download the original photo or video, just open it. When storage space is needed, only space-saving (optimized) versions of photos are kept on your Mac. Files stored only in iCloud show a download icon, which you can double-click to download the original file. When storage space is needed, only the files you recently opened are kept on your Mac, so that you can easily work offline. Store all files from these two locations in iCloud Drive. Click the Store in iCloud button, then choose from these options:
