Apple is introducing a new feature as part of MacOS 10.15 Catalina that enables you to turn your iPad into a second display. And, iPad Pro owners will be able to use their tablet as an input device with an Apple Pencil.

But, what does this mean for Mac users and how does it all work? We look at how Apple will use the iPad to improve the Mac.

Connecting your iPad to your Mac

The new Sidecar system works either with a direct wired connection or wirelessly via Bluetooth. As it doesn't use Wi-Fi, it means it will only work within a range of 10-metres rather than connecting via your home network.

Users will also need to be logged into the same iCloud account for it to work. However, it doesn't require a dedicated app that has to load on either the Mac or the iPad. Instead, users will be able to simply connect to their iPad or iPad Pro via "display settings" in the menu bar on the Mac desktop.

Mac to iPad, not the other way around

Sidecar is controlled via a new feature in MacOS 10.15 Catalina rather than via the iPad using iPadOS.

You can only initiate the new feature from the Mac rather than the other way around. This feature is designed to extend or mirror your desktop rather than work as an independent monitor for your Mac mini, for example.

Your MacOS desktop on the iPad

Once you're connected, the iPad effectively becomes a dumb display, albeit with a few nifty, extra tricks. Just as you can with a standard secondary display, you can drag apps and other things over to the iPad screen - including your mouse cursor.

The desktop screen effectively runs in an "iPad space", so you can still access other functionality features of the iPad - including "slide over" apps while using it as a display. What isn't yet confirmed is whether you'll be able to split-screen the desktop view with other iPad apps at the same time. 

Use iPad as a mirrored desktop or secondary display

As you can with current secondary displays you can choose to use your iPad to expand or mirror the desktop.

That could be really handy if you are showcasing features and don't want people to be huddled around your computer screen.

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Will come with a Sidecar Sidebar feature

In addition to expanding your desktop real-estate, Sidecar adds extra functionality through what Apple calls Sidebar.

Running down the left-hand edge of the screen, it gives you access to your most commonly used controls. These include modifier keys to enable shortcuts in supported apps.

Sidecar adds Touch Bar even if you don't have a Touch Bar-enabled MacBook Pro

Apple has also added a similar Touch Bar, as used on its latest MacBook Pro, which appears along the bottom of the iPad screen. If the app you are using supports Touch Bar it will show on Sidecar too. And no, you don't have to have a Touch Bar-enabled MacBook for it to work.

Sidecar on iPad vs Sidecar on iPad Pro

The new Sidecar feature will work on all iPad and iPad Pro models running the new iPadOS 13. Both the older and newer generation iPad Pro models will support Pencil functionality.

Pencil support in Apple Sidecar

Besides expanding your desktop space, one of other the key Sidecar features is the ability to use it as a digital notepad, marking up images or drawing using supported apps.

For Pencil support to work, the app will need to support Tablet Events. But, don't worry, lots of creative apps already do. At the moment that includes many Apple apps, but also a range of applications from third-party developers, including Adobe and Serif.

For artists, it means you'll be able to open an app like Adobe Illustrator and, using an Apple Pencil, draw on the iPad instead of using a dedicated drawing tablet from Wacom, your mouse or trackpad.

Using Markup in Sidecar

Apple's Markup feature, as found in Preview, is likely to be one of the most common uses of the remote drawing functionality.

Opening a screenshot in Preview will automatically open the file on the iPad or iPad Pro screen, allowing you to add notes and Markup before saving it back to the desktop. That's going to be really handy for designers and those that have plenty of pdfs to sign.

You'll also be able to use the feature to draw fresh notes and then import them into other apps as sketches.

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List of apps announced that support Sidecar

Apple announced a number of apps that will work with the new Sidecar feature, including many from third-party developers:

  • Adobe Illustrator
  • Affinity Designer
  • Affinity Photo
  • Cinema 4D
  • CorelDRAW
  • DaVinci Resolve
  • Final Cut Pro
  • Maya
  • Motion
  • Painter
  • Principle
  • Sketch
  • Substance Designer
  • Substance Painter
  • ZBrush

We expect the number of apps to grow considerably before the launch of MacOS 10.15 Catalina later this year.

You'll be able to see full screen apps on the iPad 

Like you already can on the Mac, you'll be able to view your apps full screen on an iPad using the usual green button at the top left hand corner of the app.

Pressing the full screen mode button will, if you want, expand the app size to take up the entire iPad screen. 

Running a monitor and an iPad as secondary screens 

According to Apple you'll be able to run both a monitor and an iPad as additional screens if you want. However, it's uncertain at this time whether you'll be able to run more than one iPad at the same time.

We would love to see a Mac with an iPad either side to create an epic cockpit experience for games or your very own mission control when on the road. 

Can you replicate Sidecar now with other apps?

There are already a number of desktop screen-extending apps in the Mac App Store that will allow you to use your iPad as an additional screen.

Popular ones include Luna and Duet Display. For those that want a dedicated stylus input, the popular Wacom Cintiq tablets work very well. 

Apple's feature will be free, included in MacOS 10.15 Catalina, and won't require further hardware or adapting and changing multiple settings.