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.
Ctrl+click or 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, in the Format Shape pane, 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.