To use Split View mode, first open an app you want to use as a split-screen app. Here we’ve chosen Safari but any app that’s compatible will do. Just open the app window; there’s no need to open it as a full screen.
Click on the window’s top bar and drag it upwards, onto the menu bar. A strip appears, offering the current desktop image and a receptacle for the app you’re dragging. Drop the window onto the plus sign to make it a full screen app.
Go back to the desktop and open the second app you wish to use as a full-screen app in Split View mode. Here we’re using Apple’s own Pages word processor app, though once again, you can use almost any app on your Mac.
Drag the window for this second app upwards, onto the menu bar, as you did with the first one. The strip appears again. Drop the second app onto the desktop you created earlier showing the first app, which is represented by an icon on this strip.
The two apps now offer a combined icon, which you can see here, labelled ‘Safari & TextEdit’. This is a single desktop, in which both those apps are running, in split view. To open them, click on the icon in the usual way.
In Split View mode, you can make full use of the two apps, just as if they were each running singly in full-screen mode. If you wish to allocate one app more space than the other, click and drag the black line that divides them.
To take one of the apps back out of full Split View mode, move the pointer to the top of the screen until the gumdrops appear; then click on the green icon, just like you would with a regular full-screen app. The app in question leaves full screen mode.
If you’ve already made an app full-screen in the usual way, that is, by clicking the green gumdrop icon, you can still drag a second app to the top of the screen and dropping it on the full-screen app’s icon, as shown earlier. You can then use the two apps side by side on your desktop.
The split view apps are treated like a desktop by macOS, just like a regular full-screen app is. Therefore, you can switch between your desktop and the split view apps by swiping the trackpad with three fingers or a Magic Mouse with two.
A useful trick with split view apps is to open two Finder windows, allowing you to manually compare and copy between two folders. To copy an item (instead of simply moving it) hold ALT while you drag an item from one to another.