how can i open the microphone in screen-record ?

Here's how to do it on a Mac:

1. Open Quicktime.
2. Go to File.
3. New Screen Recording.
4. Press the "Record" button.
5. Click the screen to record the entire area or click-and-drag around the area you want to record.
6. You can record your computer's microphone audio.
7. You can also download plugins like Soundflower

Thanks

xingoos