The Dataverse for Teams environment is automatically created for the selected team when you create an app or bot in Microsoft Teams for the first time or install a Power Apps app from the app catalog for the first time.
The Dataverse for Teams environment is used to store, manage, and share team-specific data, apps, and flows.
Each team can have one environment, and all data, apps, bots, and flows created with the Power Apps app inside a team are available from that team's Dataverse for Teams database.
Reference:
https://docs.microsoft.com/en-us/power-platform/admin/about-teams-environment