Sidecar on your Mac
With Sidecar, you can turn your iPad into a second display for your Mac. Give yourself extra space to work, draw with Apple Pencil, mark up PDFs and screenshots, and more.
Note: You can use Sidecar with iPad models that support Apple Pencil and run iPadOS 13. For more information, see the Apple Support articles Use Apple Pencil with your iPad or iPad Pro and Use your iPad as a second display for your Mac with Sidecar.
Connect your iPad. Click the AirPlay menu 
in the menu bar on your Mac, then choose your iPad. When Sidecar is on, the AirPlay icon turns into a blue iPad icon 
. To disconnect your iPad from your Mac, open the AirPlay menu and choose Disconnect. You can also disconnect by tapping 
in the sidebar of your iPad.
Tip: If you don’t see your iPad in the AirPlay menu, make sure it has Wi-Fi or Bluetooth turned on. You also need to be signed in with the same Apple ID on both devices.
Wired or wireless. Connect your iPad with a cable and keep it charged, or use it wirelessly within ten meters of your Mac.
Extend your desktop. When you connect your iPad, it automatically becomes an extension of your Mac desktop. To get started, just drag your apps and documents onto your iPad.
Mirror your desktop. To show the same thing on both screens, open the AirPlay menu and select Mirror Built-In Retina Display. To extend your desktop again, open the AirPlay menu and choose Use as Separate Display.
Use Apple Pencil. Precisely draw and create in your favorite pro apps. Just drag the window from your Mac to your iPad and start using Apple Pencil.
Or use Apple Pencil to mark up PDFs, screenshots, and images. To learn more, see Continuity Sketch and Continuity Markup on your Mac.
Note: Pressure and tilt for Apple Pencil only work in apps with advanced stylus support.
Take advantage of sidebar shortcuts. Use the sidebar on your iPad to quickly reach commonly used buttons and controls. Click the buttons to undo actions, use keyboard shortcuts, and display or hide the menu bar, Dock, and keyboard.
Use Touch Bar controls—with or without a Touch Bar. For apps that have Touch Bar support, the controls appear at the bottom of the iPad display, whether or not your Mac has a Touch Bar.
Set preferences. To set Sidecar preferences, open System Preferences, then click Sidecar. You can specify which device to connect to, change the location of the sidebar and Touch Bar on your iPad, and enable double-tap with Apple Pencil to quickly access tools.
Learn more. See Use your iPad as a second display for your Mac in the macOS User Guide.