I’m regularly struggling to get my iPad recognized by my Mac for Handoff and Keyboard/Mouse sharing. I like to be able to use a single keyboard and mouse to dive my computer and my iPad, located next to my Mac monitor.
Even after making sure that they’re on the same network and signed in with the same iCloud account, the Mac will often not “find” my iPad. Here’s a solution I’ve stumbled upon to get it to work.
iPad: Open up Settings on the iPad and turnoff Handoff (under General->Airplay & Handoff).
Mac: Open Settings->Displays. Click “Advanced…” and uncheck “allow your pointer and keyboard to move between any nearby Mac or iPad.” Click “Done” (important!)
iPad: turn Handoff back on. Make sure to toggle “Cursor and Keyboard” On.
Mac: Click “Advanced…” again. Toggle “Allow your pointer …” back on. I keep the other two options (Push and automatically reconnect) enabled as well.
On the Mac you should now be able to find you iPad under the dropdown with the + symbol and select “Link keyboard and mouse to” your iPad.
Good luck getting them arranged in any kind of convenient way though! I still can’t get that to work as expected consistently.