How to make an extra copy of my iCloud Drive documents?

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Access iCloud Drive files from your iPhone and other devices - Apple Support

 open system preferences > iCloud and uncheck the box of iCloud Drive a pop up window appears , showing to keep a copy of documents , and remove from the Mac .

( a ) if you had clicked on keep a copy , they will be archived in home folder that can be viewed by clicking on finder in the dock , take cursor on top menu bar > Go > Home > your user name > iCloud Drive ( Archive ) .

Once again double click on empty iCloud Drive box , a circle rotates setting up the box finally gets checked , make sure always turn on iCloud Drive and desktops and documents box as checked Use iCloud Drive to store documents on your Mac and iOS devices - Apple Support

Add your Desktop and Documents files to iCloud Drive - Apple Support

Use an internet browser, log into www.icloud.com , click Account Settings near the middle top of the screen, click Advanced on the next screen, click Restore Files.

Also, if you do not have Apple menu > System Preferences > Apple ID > iCloud (in the left sidebar) > Optimize Mac Storage (near the bottom right of the window) turned on, then there is always a local copy of your iCloud Drive documents (accessed via Finder "Go" menu or Finder sidebar) and they are included in a Time Machine backup.