A company is organized in GreenSpacePro as a workspace. Your company workspace is shared among all your teammates.
The first person that signs up for a company with their work email address (e.g. firstname.lastname@example.org) in GreenSpacePro will create their company's workspace.
When teammates signup for GreenSpacePro with the same work email domain (e.g. email@example.com) they will automatically join their company's workspace.
New users can also be added to your workspace by going to your GreenSpacePro Settings / Teams & Users and selecting Add New User.