A workspace is the shared home for one business, client or project. It has its own sites, team, activity and plan limits.
Everyone in a workspace can see its sites. Their role controls what they can do: Owners and Administrators manage the team and settings; Release Managers can deploy to Production; Developers work in Development and Testing; Viewers can look but not change anything.
Members cannot see your other workspaces. Create a separate workspace when a client or project needs its own team, sites or plan.