I have a folder with 5 items stored in the iCloud Drive app on my iPhone. I am trying to send an email from my phone that will include the folder - my options only seem to be to send 5 separate emails ......??
I don't think you can email an entire folder without somehow archiving it first. Try Winzip for iOS and see if that works for you. It's free on the app store.
The other person receiving the attachment may need to also have the app to open the file.