To do Alt + H + 8 + T on Mac in PowerPoint, download and install Accelerator Keys, then press Option, followed by H, 8, then T.
Command: tOGGLE cASE
This is how to do Alt + H + 8 + T on Mac in PowerPoint with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with PowerPoint.
Alt + H + 8 + T toggles the case of each character in the selected text, converting uppercase letters to lowercase and lowercase letters to uppercase. Useful for fixing text typed with Caps Lock accidentally on.