Step 1/4 : Download and install Blackhole
Quicktime player is how you screen record however it only has options to record sounds from your mic. To record internal audio you need another plugin called blackhole an audio loopback driver. Browse to the description section under installation instructions. You will find the download link which will send you the download link to your email. I choose the 16-channel version. Download and install the program.
Step 2/4 : Setup Audio midi setup
2-1 Go to your mac search and find the Audio midi setup.
Bottom left of audio midi for the next 2 steps.
2-2 Setup Aggregate device
Make sure to include Macbook Speakers.
2-3 Setup Multi-output device
2-4 Rename to Quicktime Input and Screen Recording Audio
Step 3/4 : Setup Sound Output to choose screen recording audio
Step 4/4 : Quicktime screen recording select audio Quicktime Input