Members are licensed users in your workspace.
Every Giraffe account belongs to at least one workspace, whether that is a personal workspace (for Core tier) or a shared one (for Teams and Enterprise).
Every member you add will use a license in your workspace. The license type you assign will determine their permissions for data creation, editing, or viewing throughout that workspace.
A particular Giraffe account holder does not need to be a member of your workspace to collaborate on projects, but they do need to be a member to author new projects within that workspace.
A particular Giraffe account holder can be members of multiple workspaces, using the same email. They will use up a license seat in every workspace they are a member of.