The iPhone Duo is the first iPhone that can run two apps on the screen at the same time. When unfolded in landscape orientation, Split View places two apps side by side on the 7.6-inch inner display. If you use a pair of apps frequently, you can lock them as an app pair so they always launch together.
Open two apps on the iPhone Duo
Split View on the iPhone Duo works on the inner display in landscape. There are two ways to start it.
From an app you are already using: swipe up from the bottom of the screen, pause in the center, then keep dragging the app toward the left or right edge. The app will settle into that half of the screen and the Home Screen will appear on the other half. Select the second app by tapping its icon on the Home Screen, swiping down to search for it, or swiping left to find it in the App Library. The second app will open alongside the first.
From the Home Screen or App Library: touch and hold an app icon, then tap “Open in Split View.” Tap the second app you want to open on the Home Screen, via swipe-down search, or from the App Library.
You can also open two windows of the same app when the app supports multiple windows. Apps listed as supporting multiple windows include Safari, Mail, Notes and Files. Open the app in Split View, then tap its icon again on the Home Screen or in the App Library to open a second window beside the first. To swap the two apps, swipe up from the bottom of either app, pause in the center, then drag it to the opposite side.
Lock two apps as an app pair
With both apps open in Split View, tap the divider between them. That action pairs the apps; the next time you open either app, the other will open automatically alongside it. To unpair, drag the divider all the way to the left or right edge of the screen: the app you push off will close and the remaining app will return to full screen.
Worth knowing
The iPhone Duo split is fixed at 50/50, unlike Split View on iPadOS where the divider can be resized. Also, only one app can play audio at a time, so two side-by-side video feeds will not both produce sound simultaneously.
Those are the available Split View and app-pairing behaviors on the iPhone Duo.
