Hi
Are you trying to revoke file sharing permissions for external and guest users within your organization?
Teams tag is mainly focused on the general issue of Microsoft Teams troubleshooting, files on Teams are essentially kept in OneDrive and SharePoint, so your question is not in our support scope.
You can contact the administrator and set file sharing permission in SharePoint Admin Center, for more details, please refer to:
Microsoft 365 guest sharing settings reference | Microsoft Learn
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.