On the Mac, there's an iCloud Drive folder, and on iOS devices and Windows PCs, there's an iCloud Drive app. On other devices, iCloud Drive can be accessed through a browser.
iCloud Drive
On the Mac, there's an iCloud Drive folder, and on iOS devices and Windows PCs, there's an iCloud Drive app. On other devices, iCloud Drive can be accessed through a browser.
iCloud Drive How Tos

How to Share iCloud Folders on iPhone and iPad

How to Share Files Stored in Your iCloud Drive
iCloud Drive Articles

Apple Says iCloud Folder Sharing in macOS Catalina Coming 'This Spring'

Google Drive Updated to Play Friendly With Apple's Files App

Fix Incoming for Google Drive Issue Preventing Many File Types From Opening in Apple's Files App [Updated]

Dedicated iCloud Drive App Included Within Settings of iOS 9
