on the View bar to expand or reduce the current Document View. You may also choose a preset zoom factor or enter a desired factor directly.You can enlarge or reduce a page to any size allowed – within the range of the minimum and maximum zoom levels. When you zoom-in to a size larger than the window, you can use the Hand tool to move the page.
Using the Zoom controls
Click the Zoom buttons beside the magnification level box on the View bar to expand or reduce the current Document View. You may also choose a preset zoom factor or enter a desired factor directly.
Using the Zoom-in / Zoom-out tool 
Select the Zoom-in button (in the Main Toolbar) to enlarge, or the Zoom-out button to reduce the view; or choose Zoom In or Zoom Out under Zoom in the View menu.
While one of the Zoom tools is selected, you can press the Ctrl key to switch between the Zoom-in and Zoom-out tool.
Using the Dynamic Zoom tool 
This tool lets you to enlarge or reduce page view according to the mouse movement. Drag up to zoom in, drag down to zoom out.
Using page thumbnails to zoom
A red box in the thumbnail shows which part of the page is being displayed. Drag corners of this box in the Navigation panel, to change the part of the page that is visible.
Note
Use the Hand tool to move around the page. Define its behavior in Edit > Preferences > General > Miscellaneous.