Make a public team private in Microsoft Teams

As a team owner, you can change a team’s privacy setting from public to private, if your organization allows it.

When a team is private, only team owners can add new members.

Public teams are visible to everyone from the teams gallery and you can join them without getting approval from the team owner.

Change a team's privacy status

As a team owner, you can change the privacy settings for your team from public to private (or vice versa), depending on the admin settings.

In Teams, go to Chat or Teams, depending on your layout.
Select More options next to Your teams and channels .
Find the team you want to change, and select More options > Manage team .
Select Settings > Team details, then select Edit.
Under Privacy, choose Private, then save your changes.

After you make a team private, people can no longer find or join the team unless a team owner adds them.