post https://{server}/api/v2.1/admin/organizations/
Add a team (organization) with its name and admin credentials.
In the request body, define the new team admin's admin_email, admin_name and password.
SeaTable does not automatically create a workspace for a newly added user: the with_workspace parameter is false by default. If you would like your new user to have a workspace when they are added (so that they can start operating workspaces and bases right away with API requests), make sure you set true for this parameter.
Otherwise, their workspace will only be created when they login to the SeaTable web interface for the first time.