Note: Team owners can delete a team from the desktop or web app.
If you want to delete a team (and you’re the team owner), go to the team name and select More options > Delete the team. Your team will be permanently removed.
Deleting a team removes the team mailbox and calendar from Exchange
The corresponding SharePoint site and all its files will also be deleted
And any OneNote notebook, Planner plan, PowerBI workspace, or Stream group affiliated with the team will also be deleted
Team owners and IT admins can recover deleted teams for up to 30 days. For more info, see Restore a deleted Microsoft 365 Group.