You can split the editor to display and edit different areas in the document at the same time.
To split an editor into multiple panes, choose View > Split Editor, or, click the icon on the right edge of the navigation bar.
To close a split editor, choose View > Close Split Editor, or click the icon on the left edge of the navigation bar.
The default orientation to split editors can be set in Settings > Window > Split editor. You can also change split orientation by choosing View > Stack Editors Horizontally (or Vertically) in the menu.