Cannot delete Documents from iCloud Drive

I'm able to delete folders and files from iCloud using Safari 11.0.1

If you are using Safari I would quit out, then restart Safari while holding down the SHIFT key

you may need to disable some 3rd party extensions if you are running them.

what's happening when you try to delete them?

for further analysis you may post an etrecheck report

www.etrecheck.com

go to icloud.com and you can manage them from there you should see a screen like this

is this where you are, or are you using iCloud from a computer or iOS device like an iPhone?

where are you trying to delete them from? iOS, OS X, iCloud.com ?