It’s easy and free to record video on Mac with QuickTime Player, but if you want to record the internal audio on Mac as well, to achieve this you need a way to route the audio playing to QuickTime and a free program called SoundFlower can do you a favor. It’s an extension to Mac devices that allows audio information to pass into other applications. So please follow the steps below to record Mac screen with internal audio by using QuickTime Player.

Step 1. Download SoundFlower from https://soundflower.en.softonic.com/mac and set it up.

Step 2. After SoundFlower is installed successfully, restart your Mac computer to refresh all controls. Then go to system preferences and visit the sound tab. Click the sound output option and select SoundFlower (2ch) as your active output for the later QuickTime screen recording.

Step 3. Use Finder to find QuickTime Player and launch it to start screen recording on your Mac.

Step 4. Click File on the top menu bar and choose New Screen Recording.

Step 5. There is a drop-down button besides the red recording button, click it to select Soundflower option in order to record the system audio.

Step 6. Now you can start recording your Mac screen by simply hitting the red circle icon on the screen. You are allowed to record the full screen or drag your mouse to customize the area you want to record. Once the recording process is complete, you can click the stop button on the top of the menu to stop recording. Before you save the recorded video and give it a name, you are able to preview it to confirm whether it meets your demand.

Step 7. After you finish QuickTime screen recording on Mac, you need to disconnect Soundflower from audio input so that you can get back your audio on speakers. Just go to System Preferences and select sound settings, in output section select Internal Speakers as destination.

Record Screen with QuickTime on Windows： https://www.vidmore.com/record-video/quicktime-screen-recording/