Usually when you're creating a presentation, you'll use Normal view. While using this view, you may need to resize the window panes to better fit your needs.
The Zoom feature can come in handy when the text or object you want to work with is too small for you to see. Zooming in on a slide makes it appear larger on screen; zooming out of a slide makes it appear smaller.
Click the Zoom In ( - ) or Zoom Out ( + ) buttons on the status bar.
You can also use the Zoom button on the View tab of the ribbon to open the Zoom dialog box and choose a new zoom level.
Click the View tab.
The Zoom group on the View tab of the ribbon includes a few more ways to control the zoom level.
Click Fit to Window.
The zoom level changes so that the entire slide is visible in the window.