The Stereo Mix device should now be visible.In the Sound window, click the Recording tab, right-click in a blank space in that tab, and select Show Disabled Devices from the drop-down menu.Open the Control Panel on your computer and click Hardware and sound, then the Sound icon in the Control Panel window.If Stereo Mix is not available, it is likely disabled. In the Device drop-down list, select the Stereo Mix option.In the Preferences window, in the Devices section, locate the Recording section.In the menu bar at the top of the Audacity window, click Edit, then Preferences.Open Audacity using the shortcut on your desktop, or run it from your Start menu.Once the download is complete, run the setup program and follow the steps to install Audacity on your computer.

Download Audacity from the Audacity official website.

It's best to use an online service, as discussed above, to download audio from a YouTube video. Therefore, the steps in this section will not work for you. If your computer has an integrated sound card, you'll not be able to download streaming audio.

Audacity ffmpeg is require to proceed