If you add more text to a placeholder, like a text box, than the placeholder can contain, text resizes to a smaller font to fit in the placeholder. That is Autofit.
When you type text in a placeholder in Microsoft PowerPoint, it becomes a text object
Alignment ist he horizontal placement of text in a placeholder in PowerPoint.
solid line
placeholder text
the Autofit Options button
the Autofit Options button
text control
controlTemplateA templateIt
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The text may extend beyond the placeholder. If the option to wrap the text has been set, it can go onto a new line. The creator may take other approaches, such as changing the font size of the size of the placeholder or maybe rephrasing the text so that it is shorter.
Hidden text