A user can have a direct circle role which determine his user rights. Each team will also have a circle role, which all team members will then indirectly have. User rights can thereby be given directly or indirectly via team membership.
Even though it is possible to setup direct circle roles per user, it is highly recommended to create teams, add users and then assign roles to the teams. See more on teams here. In this way it is also easier to assign work and mention users in comments by simply using the team name.
The three different Circle roles each require a different user license. A user will only take up one user license for the entire Site, depending on the most “expensive” user role he has.
Limited User – Limited Users are allowed to view all items in the Circle and can only edit stories or participate in the workflow etc. if explicitly assigned to do so. They can however comment on all items in order to participate in any discussion. They can also create new issues, ideas or stories, but only in the Inbox – and cannot edit them afterwards. This role requires the Limited license.
Regular User – Regular Users can do the same as Limited Users. They can additionally create and edit stories and assign other users/teams, follow changes, convert story type, participate in the workflow and move stories in the Storymap. They can plan stories in the Product Backlog and create relations between stories. They can also add attachments to any story. This role requires the Regular license.
Leadership User – Leadership Users can do the same as Regular Users. In addition they can manage milestones, releases, sprints etc. They can also edit Roadmap, setup circle configuration, create teams and invite/remove users. Furthermore, deleting stories etc can only be done by a Leadership User. In Scrum, this role is synonymous with that of a Product Owner. This role requires the Leadership license.