Select some text in Word or PowerPoint, then press Shift+F3. It’ll toggle between three possibilities for text capitalization:

Initial Letter Case

ALL CAPS CASE

lower case

So, if you have selected some text like “siX MILlion Dollar mAn” each time you press Shift+F3 you’ll see it switch between “SIX MILLION DOLLAR MAN” and “six million dollar man” and “Six Million Dollar Man”.

However! If you add some punctuation (like a period) at the end of what’s selected, instead of using Initial Letter Case, it’ll only capitalize the first letter of the sentence. So “I wiN!” will toggle between “I WIN!” and “i win!” and “I win!” (and not ever show “I Win!”).