Deleted Documents folder doesn't show up anymore iOS-HELP (File App)
After a while without doing anything manually iCloud will do an automatic re-sync and the Documents folder will reappear! So no problem, just 10-20 minutes and done!

If it doesn't show up in 1 hour or so, try to "manually re-sync" iCloud by using the switch in the Setting on one of you iOS devices.
So:
Settings>"Your name">iCloud>scroll down>iCloud Drive
Switch OFF and ON one time, and then wait again for 10-20 minutes (slower the internet, slower the sync).