If you're using macOS Catalina, open the Apple TV app, choose TV > Preferences from the menu bar, then click Files.Store in iCloud selects Enable Messages in iCloud. In Messages, choose Messages > Preferences, then click iMessage.Store in iCloud selects iCloud Photos and Optimize Mac Storage. In Photos, choose Photos > Preferences, then click iCloud.Store in iCloud turns on the Desktop & Documents Folders and Optimize Mac Storage settings.

In macOS Mojave or earlier, choose Apple menu > System Preferences, click iCloud, then click Options next to iCloud Drive.

To turn off iCloud Drive entirely, deselect iCloud Drive. Then click Options next to iCloud Drive: Store in iCloud turns on the Desktop & Documents Folders setting. If you're using macOS Catalina, choose Apple menu  > System Preferences, click Apple ID, then select iCloud in the sidebar: Store in iCloud turns on the Optimize Mac Storage setting on the right.

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.

How to declutter mac with macos sierra