Transfer a large amount of PDF files from PC to Adobe Reader (on iPad)
The latest version of iTunes removed much of the abilities to upload directly to an app.

While I don't know a shortcy, you could upload the files in one of two ways (making sure your device is connected via USB for the quickest upload).


A Personal favourite is WALTR, but it's a paid option. You just drag your media into the Waltr screen and it uploads it. It will go to iBooks, however (I'm not sure about your specific requirement about Adobe Reader).
Something more apt could be to copy the files into the files section that's created when you have the iCloud Windows app from Apple and upload the files into a folder there. I'm certain (but do not actually know) that you can then open the files using the file browser within Adobe reader, or the sharing function from the Files app on your device.


I really hope this helps give some guidance.