Try below given steps to fix the issue of Headphones not showing up in Windows 10:-
- First of all, try manually enable the headphone device.
- If the headphone device is not shown in the device manager, you may need to install the driver.
- However, this method is not the best solution for the problem if your headphones are not showing up.
- This solution may only be temporary and may not work if you can't afford to buy a new one.
Also visit here:-
https://educatorpages.com/site/worldzo/pages/fixes-for-headphone-not-working-in-windows-10?
https://worldzo.hpage.com/fix-headphones-not-showing-up-in-playback-devices-in-windows-10.html
http://worldzo.bravesites.com/entries/windows/headphones-not-working-in-windows-here-are-some-fixes