With Universal Control, you can use the keyboard and mouse or trackpad connected to your Mac to work across your Mac and iPad when they’re near each other. You can even connect an additional Mac or iPad and work across three devices. When you use Universal Control, you can open and use apps, enter text, and drag items across devices. If an external keyboard and mouse or trackpad are connected to your iPad, you can use them to work across both devices too.
You can use Universal Control with your Mac and iPad.
Make sure of the following:
Both devices have signed in with the same Apple Account on both devices.
Make sure that both devices have Universal Control: Use a single keyboard and mouse between Mac and iPad.