Keystroke: ⇧ + F3
This is a "toggle" command which allows you to change the case of the currently selected (highlighted) text to one of three alternative formats as shown below.
All caps (all letters capitalized):
THE QUICK BROWN FOX JUMPED OVER THE LAZY DOGS.
No caps:
the quick brown fox jumped over the lazy dogs.
Mixed case (the first letter of each word capitalized):
The Quick Brown Fox Jumped Over The Lazy Dogs.