In Word 2013, what you really want for finding text is the traditional Find dialog box, the one that lived in the neighborhood before the Navigation pane rolled into town.
To unleash the Advanced Find command, obey these steps:
Click the Home tab on the Ribbon, if necessary.
You need to access the Editing group, which is found on the Home tab.
Click the menu arrow by the Find command in the Editing group.
The arrow is that down-pointing triangle next to the Find command button.
Choose Advanced Find.
What you see is the traditional Find dialog box, which is more powerful and precise than the Navigation pane.
Click the More button.
Upon success, the Find and Replace dialog box grows taller, with a bunch of options and doodads showing at the bottom.
Select the Match Case option under Search Options to instruct Word to pay attention to the case. Otherwise, case is ignored
Use the Find Whole Words Only option to look for words such as elf and ogre without also finding words like shelf and progress.
The Sounds Like option allows you to search for homonyms, or words that sound the same as the search word. You know: their and there, or deer and dear, or hear and here.
To change every variation of the search word, put a check mark by the option Find All Word Forms in the Advanced Find command’s dialog box and type the search word in the Find What box. Click the Find Next button and you’re on your way.