There are several ways to type an exponent on your Mac, depending on the program you are using. In addition to a keyboard shortcut that works in both native Mac programs and in Microsoft Office, you can also manually shift your text from normal case to superscript.
Your Mac supports a superscript keyboard shortcut. First type the entire equation or phrase in normal case in your Microsoft Word or Pages text editor. Then, use your mouse to highlight the portion that needs to turn into an exponent. Hold down "Control-Command-Shift-+" at the same time and the highlighted text will turn into superscript text.
In native Mac programs like Pages, you can turn a number or letter into an exponent using the Format tab. Type your text and highlight the section you want to turn into an exponent. Under Format, choose "Font," "Baseline" and then "Superscript." This method also enables you to create a subscript.