When typing text in word document, you can always change the text to uppercase or lowercase using the SHIFT key or CAPS LOCK key on the keyboard.
Sometimes, you already typed something, but then want to change all your typing into uppercase (capital letter words). Of course, you can delete and retype them in uppercase mode. In case, you have fullpage of words to retype, it is a waste of time.

Do you know that you can actually use shortcut keys to easily change the case mode of your typing text?

In Microsoft Word, user can change the case mode of a text by first selecting it,  holding the SHIFT key to toggle it with the F3 key for case switching to “UPPERCASE”, “lowercase”, or “Title case”.

Thus, if you select a word “hello”, when toggling it using (SHIFT + F3) will give you three cases of mode:
“HELLO”, “hello” and “Hello”.