How do I save Adobe pdf files to iCloud Drive?

Here's the workaround to save a file open in Acrobat on your iPad to your iCloud Files app: Save the file to your iPad from within Acrobat.  Then go to the Files app and select Recents.  Then press and hold the name of the file (don't tap or the file will open).  A menu will appear that should include the Files app. Tap that and then select the location where you want to save the file.

I'm having the same problem. If Adobe is deliberately doing this then it is very irritating and childish of them. 

Hi Jason,

Hope you are doing well.

Acrobat uses the iOS File Browsing feature to help you find and connect to any of your file storage providers. Please follow the instructions given under custom-cloud-locations:

https://www.adobe.com/devnet-docs/acrobat/ios/en/openfiles.html#custom-cloud-locations 

Also, make sure that you have got the most recent update installed for Acrobat Reader mobile app and iOS.

Thanks,

Akanchha