Different roles have different type of access to the feedback portal:
Observers: they can upvote, and submit a new insight.
Members: can set ideas, lists, and labels visible on the roadmap, and they can hide them as well. Members can turn on/off and edit public descriptions. These settings can be managed on the 'Idea" screen. They can rename the roadmap and extend it with a description on the 'Public roadmap' view.
Subscription Admin, Admin: can invite observers.
Find out more about managing user roles here.