Universal control

Universal control is still in beta version, and some feature might be implemented in the future.

In order to transfer files, I'd suggest that you use Airdop instead, as per this support article:--> How to use AirDrop on your iPhone, iPad, or iPod touch - Apple Support

Regards

Giulio

It's possible to drag a file (or image) from a Mac to an iPad using Universal Control. The catch is, you need to drag it into an open app on the iPad that can accept that kind of file.

To demonstrate:

On the iPad side, first open the Files app and select some location (which can be either on the iPad itself, or some place in iCloud).

On the Mac click & hold the cursor on a .pdf file with your mouse, Then drag the file (actually, that'll be a copy of the file) along with the cursor over to the iPad. You might see the file name attached to the cursor, but even if you don't, you should still see a '+' sign in a green dot whenever you hover the cursor over an open app that can accept the file. Drop it there when you see that.

Notably, you cannot drop a .pdf file (or any other kind of file from the Mac) onto the Home Screen of the iPad. Unlike a Mac's Home Screen, an iPad's Home Screen doesn't accept dropped files.