. Click the Design tab of the toolbar ribbon, and then, near the right end, click Slide Size. On the Slide Size menu that appears, select More Options.
A PowerPoint 2010 presentation can either use a portrait orientation, which arranges the slides vertically, or a landscape orientation, which arranges them horizontally. By default, PowerPoint slide layouts are set up in landscape orientation.
The Slide Size dialog box opens. In the Slide Size dialog box, select Portrait, and then select OK. When PowerPoint Online is unable to automatically scale your content, it prompts you with two options:. Maximize: Select this option to increase the size of your slide content when you are scaling to a larger slide size.
Choosing this option could result in your content not fitting on the slide. Ensure Fit: Select this option to decrease the size of your content when scaling to a smaller slide size.
This could make your content appear smaller, but you’ll be able to see all content on your slide.