Imagine this scenario: you place a text box on your slide — then you change the color of the font, reduce or increase the font size, set autofit options, tweak the margins, etc. At this point of time you are happy with your settings. Then you add another text box in the next slide — and you realize that this new text box needs to look the same as the text box you created earlier! No — you do not have to change all settings again — there are two ways of making the new text box possess the same settings as the older one.
Learn how to set a formatted text box as your default text box in PowerPoint 2013 for Windows.

