I had a question come up today, and I realize I haven’t mentioned this feature before. If you are sharing your screen in a Microsoft Teams meeting and you want to play a video for people, they may not be able to hear it (even though you can hear it perfectly fine). You need to use the Include computer sound option to let everyone else hear what you’re showing. Here’s how that works…
When you share content in your meeting, make sure the Include computer sound option is turned on (it’s off by default):

Once you do that, every sound your computer makes (music files, videos, notifications, etc.) will be heard by all the attendees as well as any recording that may be occurring.
For additional information, check out Share sound from your computer in a Teams meeting or live event.