Apple Merges "iCloud Documents and Data" into iCloud Drive. Last May, Apple Apple announced that it would be merging its iCloud Documents and Data service into iCloud Drive in May of 2022, and that transition has now been completed.
As noted in a support document updated today, users who previously relied on iCloud Documents and Data for syncing files across devices will need to turn iCloud Drive on in order to see their files.
iCloud Documents and Data, our legacy document syncing service, has been discontinued and replaced by iCloud Drive. If you used iCloud Documents and Data, your account has been migrated to iCloud Drive.
If you used the iCloud Documents and Data service, you need to turn on iCloud Drive to see your files. When you switch to iCloud Drive, the amount of storage space your saved files use in iCloud doesn't change.
Apple's support document provides instructions and minimum system requirements for iCloud Drive on iOS devices, Macs, and on the web at iCloud.com.
The vast majority of iCloud users already have iCloud Drive enabled, so they won't see any changes. But for users who had iCloud accounts prior to the introduction of iCloud Drive in 2014 and never enabled it, perhaps to maintain compatibility with pre-iOS 8 and pre-OS X Yosemite devices that couldn't support iCloud Drive, they will now need to turn it on in order to regain access to their files.
The older iCloud Documents and Data service kept cloud-synced data stored in folders specific to a given app, only allowing access to the data from that app. With iCloud Drive being a more full-featured syncing service, all of those files can now be accessed from a single location: the Files app on iOS and iPadOS, the iCloud Drive section of Finder on macOS, or the iCloud Drive section of iCloud.com.