A team member is a user that is part of the team. Team members can easily find each other and start conversations. Team members can create and delete conversations, add and remove team members in conversations, and invite guests to a team conversation.
The team admin is a team member with administrator rights, which allow them to add or remove other team members. Team admins can also promote and demote users from members to admins/owners and update team settings. The team can have multiple team admins.
The team owner has the same rights as the admin, plus access to the billing section of a team.