Make sure your iPad and computer support screen extension
Update your iPad and computer to the latest software
Connect both devices to the same Wi-Fi network
On Mac, open Control Center and select Screen Mirroring or use Sidecar
On Mac, go to System Settings, then Displays, and add your iPad as a display
On Windows, install a third-party app such as Duet Display, Splashtop Wired XDisplay, or spacedesk
Install the same app on your iPad and computer
Connect the iPad to the computer with a USB cable or Wi-Fi, depending on the app
Open the app on both devices and follow the pairing steps
Set the iPad to extend the display instead of mirroring if available
Adjust display settings such as resolution, arrangement, and orientation
Use the iPad as an extra screen for apps, documents, or reference material