Board Admins can change the role of anyone who is part of a board team,
e.g. upgrade a Visitor to a
Team Member or even Board Admin.
Team Members have read+write access: they can make all kinds of changes to a board,
such as adding, changing or moving cards on a Task Board or Scrum Board, or adding new items to a Whiteboard.
Visitors have read-only access: they can get a real-time view of a board, but they cannot make
changes, and they cannot see any of the chat that takes place within a board team.