How does an IT admin allow Fileport in Teams?

Fileport is in the Teams Store, so people can add it unless your organization blocks apps from outside. In the Teams admin center, open Teams apps, then Manage apps, search for Fileport and allow it. A setup policy can add it for everyone, or pin it.

The app asks for no permissions in your organization and signs no one in. Microsoft sends Fileport only the Fileport links people paste and the steps of sending with Fileport, and Fileport keeps none of the identifiers that come with them but the sender's Microsoft ID, for the day a send lasts. A send also keeps the sender's name and a meeting's name to show on its page. The channel, the team and the address they sign in with reach that page only in their browser.

Once it's allowed, it also works in Outlook on the web and on Windows. To turn it off, block it in Manage apps.