Turn on Teams in your organization
Microsoft Teams is turned on for all organizations. You can control access to Teams in your organization with user-level licensing. To learn more, see Manage user access to Teams. To learn more about managing individual licenses, read Microsoft Teams service description.
As an administrator for your organization, you can assign user licenses to control individual access to Teams, and you can allow or block what content sources can be used in Teams. See Manage Microsoft Teams settings for your organization or Admin settings for apps in Microsoft Teams for more information.