Office 365 - Microsoft Teams - Change Your Status in Teams
Information and links from Microsoft support about how to change your status in Teams.
If you want to make sure people know when you’re busy or away from your desk, set your status in Teams. The little dot on your profile indicates if you’re available or not.
Teams will automatically set the status in some cases, like when you’re in a call. To explicitly set it yourself, go to your profile at the top of Teams and select one from the list.