QuickTime Player is a convenient way to record audio and video from your Mac. You can select sources for audio that include any real or virtual microphones or sound inputs and from video sources that include nearby iPhones, iPads, and Apple TVs.
After you press the Record button, you might not realize you have an option other than clicking the button again, now in the form of the Stop button. Clicking Stop ends the recording, and you’re prompted to save the resulting file.
However, there’s a hidden option you can’t access from any menu: hold down Option and the Stop icon changes to a Pause one. Press the Pause icon, and it, as expected, pauses.
Read more at Macworld.com