mac-apps-split-view.md

Use two Mac apps side by side in Split View

1. Hold down the full-screen button in the upper-left corner of a window.
2. As you hold the button, the window shrinks and you can drag it to the left or right side of the screen.
3. Release the button, then click another window to begin using both windows side by side.

Reference

Use two Mac apps side by side in Split View