One of our users recently deleted Adobe Reader from his iPad by accident which also removed more then a 1000 PDF files stored in the app.
Fortunately the Acrobat Reader was enabled for iCloud backups (Settings > Apple ID > iCloud > Adobe Acrobat).
We restored the backup on another iPad then reinstalled the Acrobat Reader app but this did not bring back the files. Using a third party tool we were able to see that there is 1GB of Acrobat data stored in that particular backup.
My question is how do I retrieve the PDFs from the iCloud backup?
When you have reinstalled the Adobe Acrobat Reader mobile application did you check the iCloud storage of the application?
You may check once if you could find anything in this way.
Go to Adobe Acrobat app>My Document>Click on drop down arrow> Tap More Locations>iCloud Drive
Else you need to download the each file from iCloud drive and then "Open In" Adobe Acrobat Reader.
Let us know the update on this.
i don't know how to restore if from icloud but i know that disk drill tool may be helpful for you, it's for Mac and Windows.