Microsoft Teams has a Status feature (also sometimes called Presence) that lets people know your availability. This feature works automatically, but you can also control it manually if you need to:
To access it, click on your portrait in the top-right of Teams, and then mouse-over your current status to see your available statuses.
If there’s a meeting going on in your calendar, Teams will auto-update your status to “In a Meeting,” or to “On a Call” if you’re on a Teams call. If you’re idle for a period of time, it will auto-update to “Away.”
You can manually choose a different status if you want to override the auto-chosen status. Just be sure to click on “Reset status” when you’re done to let Teams go back to automatically updating your status.
Lastly, you have an option to “Set status message” to let people know what’s up, such as “On a lunch break, back at 1pm.”