Set the margins for text inside text boxes and shapes
Text on your PowerPoint slide is contained within text boxes and shapes. You can set the left, right, top, and bottom margins for the text within a text box or shape.
Right-click the border of the shape or text box for the margins you want to set, and then click Format Shape.
On the right side of the PowerPoint window, click Text Options, and then click Textbox .
To set the margins, use the up and down arrows or type the measurements you want in the boxes. You’ll see the margins change in your presentation as you do this. Check Wrap text in a shape for text to appear on multiple lines.
If you're looking for information about how to set page margins in PowerPoint, this feature isn't currently offered. However, there are a couple of things you can try that may give you more control over the size and shape of your slides: