To use Touch ID or Face ID with your Files Cloud or Acronis Files Advanced app, you need:
A device with a set passcode and Touch ID or Face ID.
An app password for Files Cloud/Acronis Files Advanced set, with Touch ID or Face ID option enabled.
In Files Cloud, the app password is optional. In Acronis Files Advanced, though, it might be required by a mobile security policy. In such a case, users without an app password will not be able to use the app.