AutoCorrect is a feature in PowerPoint that will automatically correct a common spelling error or convert specific keystrokes to a symbol.
For example: If you need to indicate on your slide that some text is a Trademark, the symbol is TM. In PowerPoint, you would simply type (tm) and the trademark symbol would be entered on the slide.
You can also tailor AutoCorrect to use as a quick way to enter repetitive, lengthy phrases. This tutorial on Using AutoCorrect to Your Advantage takes you through a sample scenario.