universal control

Did you try:

Open the Files app on the iPad.

Drag a file from the Mac into the Files app on the iPad.

[There may be other apps that you can drag a file into as well, but what I know is that you can't drag a file onto the Home Screen of an iPad.]

See this link and at the bottom of the link are the system requirements to make sure you have the required systems/software --> Universal Control: Use a single keyboard and mouse between Mac and iPad - Apple Support

I don't own a Mac. Did you look at the list of devices which are compatible to ensure you own such a device?