Place the insertion point where you want to begin dictating, or select the text you want to replace.
Choose Edit > Start Dictation (from the Edit menu at the top of your screen).
If you haven’t used dictation before, follow the guided setup instructions that appear.
Tip: When dictation is set up, you can also press the Function key (fn) on your keyboard twice to start dictation.
When the microphone appears, begin speaking.
To add punctuation speak its name (for example, comma or apostrophe).
Click Done below the microphone when you’re finished.
To change the shortcut key for dictation, or to change the language, open Dictation & Speech preferences on your Mac.
To learn more about dictation, go to Mac Help. Click the desktop to switch to the Finder, choose Help > Mac Help (from the Help menu at the top of your screen), then search for dictation.