Part of macOS

`bird`iCloud Drive

○ Leave it

Syncs iCloud Drive and Desktop & Documents.

What it is

Moves files between your Mac and iCloud Drive.

Why it might be busy

After adding or changing many files in iCloud Drive. Usually until syncing finishes.

If you stop it

macOS starts it again straight away. Leave it.

○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.

From Procession’s guide, in the words the app shows.