AutoText is an option that saves time by typing things that are repeated without having to type the whole thing. AutoCorrect is an option that automatically corrects spelling and grammar. If you are typing something that is commonly used, it will bring up a Tool Tip with the word it recognizes.
To check and see what text is set to AutoCorrect go to Office Button > Word Options > Proofing > AutoCorrect Options.
To add more text to AutoCorrect type what you want replaced in the box labeled Replace and what you want to replace it with in the box labeled With and hit “Add”.Click OK once you are done.