Split screen lets you view two apps side by side.

Windows 10/11:
 Open the first app or window
 Press Windows key + Left arrow to snap it left
 Open another app → it snaps right
 Drag divider to resize

Mac:
 Open the first app
 Hover over the green maximize button (top-left)
 Select Tile Window to Left/Right of Screen
 Choose another app for the opposite side