Can we find duplicate files so that we can delete them on the iCloud?

Hello farisalami,

Welcome to Apple Support Communities. 

We understand that you would like to be able to locate duplicate files and delete in iCloud. We are happy to point you in the right direction.

There’s not a way to do this. Please leave Apple feedback here: Product Feedback - Apple

Let us know if you have further questions.

Take care.

Open finder > iCloud Drive > click on personal folder or document , in its sub folder you can find duplicate file ( it can be searched using finder spotlight search ) just type duplicate file it will be searched in my Mac , right click over it and move to bin .

See the articles Narrow your search results on Mac - Apple Support

Delete files and folders on Mac - Apple Support

Note : the file will automatically delete from iCloud.com when iCloud Drive and desktops and documents box is turned as on from Mac system preferences .

If you’re looking for duplicate files on your Mac, you’ll need to use a third-party tool. If you d sync with iCloud, the files in the cloud are not duplicates; erasing the files on your computer also erased in the cloud