Have you ever experienced playing a video during a Teams presentation and that the other participants could not hear the sound?
The option to share your computer's sound is disabled by default. Fortunately you can enable it quite easily from the menu where you share content e.g. your presentation:
During the presentation you can also enable or disable the sharing of computer sound via the sharing controls in the top:
For more information and troubleshooting check out: Share sound from your computer in a Teams meeting or live event.