In Read Mode, the PDF will be displayed in a way that hides much of the interface, including the navigation pane, toolbar, and status bar, to maximize the document display area. To switch to the the Read Mode, go to VIEW menu > click Read Mode. You can press the shortcut key "Ctrl + H" on the keyboard.
In Read Mode, you can press Ctrl+Tab to switch between different documents. Hit Esc to exist the Read Mode.