If you're typing standard text on a Mac, the keyboard has all the alphabetic characters you'll need. However, specialized formatting takes a little extra know-how. Most Mac programs support subscripts, and they use the same basic keyboard shortcuts for activating subscripts. Using the correct keystrokes, you can type subscripts on virtually any Apple computer.
Open the program in which you want to type subscripts. Many word processors, graphic-design programs and email providers support subscript formatting.
Press and hold the "Command" key. This key is sometimes called the "Apple" key because it has the Apple logo on it.
Press and hold the "Option" key.
Press and hold the "Shift" key.
Press the "Plus" key on your keyboard. You can release all three keys and begin typing subscripts. To turn the subscript formatting back off, press the "Command," "Option," "Shift" and "Plus" keys again.