By default, the Zoom toolbar contains tools used to select markups and text as well as pan and zoom in and out on a PDF.
If the toolbar is currently hidden, go to View > Toolbars and select it to show it.
Pan (SHIFT+V): Click and drag to pan the image.
Zoom (Z): Click to zoom in; hold
Measure (M): Launches the Measure tool and opens the Measure tab.