Workspaces
A workspace is the security boundary for everything it contains.
A workspace provides the security visibility boundary. So for instance a workspace like “Company X” would hold all the activity of Company X and everyone in company X has read access.
Inviting someone to one of your workspaces does not give access to others. Views, jobs, and everything else are contained inside a workspace.
See setting up a workspace for how to invite participants.
A workspace is billed to the account of the user that creates the workspace.
The left nav workspace dropdown has workspace settings and creating a new workspace or a new view in a workspace:

Also on the left nav, below the workspace dropdown, are the switch workspace, add collaborators, and compose controls.