You can access iCloud Drive and store files, create folders, and share documents with friends and family. You can access your content from all your devices where you’re signed in to the same on your iPhone.
Tap Browse at the bottom of the screen.
Tap iCloud Drive below Locations.
If you don’t see Locations, tap Browse again. If you don’t see iCloud Drive below Locations, tap Locations.
To open a folder, tap it.
See Share files and folders in iCloud Drive on iPhone