Change the default font for text boxes in PowerPoint

In PowerPoint for Microsoft 365, the default font for text boxes and shapes is Calibri, with a font size of 18 points.

To change the default font for text boxes, follow the next steps:

   1.   Create a new text box in your presentation:

On the Insert tab, in the Text group, click Text Box:

   2.   Apply any formatting you need. You can change the fill color or add an effect, change the text color, style, or weight of a line, or make any other changes:

   3.   Select the text box, right-click the border, and then click Set as Default Text Box on the popup menu:

Next time you add a new text box, PowerPoint will use the formatting you applied:

See also this tip in French: Comment changer la police par défaut pour les zones de texte dans PowerPoint.