Use one keyboard and mouse to control Mac and iPad
With Universal Control, you can work across up to three devices (for example, a Mac and an iPad) using a single keyboard and mouse or trackpad. You can also drag items between devices.
To use Universal Control, make sure of the following:
You’re using supported models of Mac and iPad.
Your Mac has macOS 12.3 or later and your iPad has iPadOS 15.4 or later.
You’re signed in with the same Apple ID with two-factor authentication on all your devices.
You have Wi-Fi, Bluetooth and Handoff turned on in System Settings (on your Mac) and in Settings (on your iPad).
Connect your Mac to another Mac or iPad to use Universal Control
With Universal Control, you can establish a connection between your Mac and a nearby device, then use a single keyboard and mouse or trackpad to work across the devices.
Note: If you don’t use Universal Control for a period of time, you may need to establish the connection again.
Do one of the following:
On your Mac, use your mouse or trackpad to move the pointer to the right or left edge of the Mac screen. When a border appears at the edge of the Mac screen, move the pointer past the border until the pointer appears on the other device.
On your Mac, choose Apple menu
in the sidebar. (You may need to scroll down.) Click the 
pop-up menu on the right, then choose a device below Link Keyboard and Mouse. Use your mouse or trackpad to move the pointer past the edge of the Mac screen until it appears on the other device. On your Mac, click Control Centre in the menu bar, click Display, then choose a device below “Link keyboard and mouse to”. Use your mouse or trackpad to move the pointer past the edge of the Mac screen until it appears on the other device.
The direction in which you move the pointer when establishing the connection determines which side of the display you use to connect your devices. You can adjust this behaviour by changing the arrangement of the devices in Displays settings. Click the image of the display, then drag it to the desired position.
You can set your Mac to automatically reconnect to any nearby Mac or iPad. Choose Apple menu 
in the sidebar. (You may need to scroll down.) Click Advanced on the right, then select “Automatically reconnect to any nearby Mac or iPad”.
Disconnect your Mac from another device
After you establish a connection between devices using Universal Control, the connection remains until one of the devices goes to sleep or you disconnect them.
On your Mac, choose Apple menu
Select your display on the right, then click Disconnect.
Turn off Universal Control
You can turn off Universal Control to prevent your Mac from connecting to other devices to use a keyboard and mouse or trackpad.
On your Mac, choose Apple menu
Click Advanced on the right, then do one of the following:
Turn off all Universal Control connections: Turn off “Allow your pointer and keyboard to move between any nearby Mac or iPad”.
Prevent a connection when moving the pointer to the edge of the screen: Turn off “Push through the edge of a display to connect to a nearby Mac or iPad”.
You can set an option to temporarily disable Universal Control whenever you zoom in on the screen of your Mac, so it’s easier to zoom in along the edge of the screen. See Change Zoom advanced options for accessibility.