These options allow you to align and orient the view.
Blender uses a right-angled “Cartesian” coordinate system with the Z axis pointing upwards. Left/ Right corresponds to looking along the X axis, Front/ Back along the Y axis, and Top/ Bottom along the Z axis.
You can select the viewing direction for a 3D View with the View menu entries, or by pressing the hotkeys. You can select the opposite directions if you hold Ctrl while using the same numpad shortcuts.
These operators change the view to be aligned with the specified global axes: