This installs SOME Desk Host in your Applications folder and a virtual microphone (SOME Desk Mic) that lets your iPad's mic reach dictation apps on this Mac.

Installing the microphone briefly restarts Core Audio, so audio on this Mac will cut out for a second or two. Quit anything you are recording with first.

After installing, SOME Desk Host will ask for Screen Recording and Accessibility permission — it needs both to show this Mac on your iPad and to pass your keyboard and mouse through.