Slide Aspect Ratio: Change Presentation Aspect Ratio from Widescreen to Standard (and Vice Versa)
PowerPoint defaults to widescreen slides in all new presentations. However, you can change your presentation’s aspect ratio from Widescreen (16:9) to Standard (4:3), and also do the reverse. PowerPoint has some features up its sleeve that make these changes of aspect ratios easier to understand, and some quirks too!
To learn more, choose your version of PowerPoint. If we do not have a tutorial for your version of PowerPoint, explore the version closest to the one you use.