How does the invitation process work on pCon.login?

Using a form within the pCon.login account, administrators can invite other people from your organization. If you don’t yet have a pCon.login account, have an administrator from your organization invite you. You will then receive an e-mail with a confirmation link. Invitations are only valid for a limited amount of time. If you don’t react within this time frame or if the invitation is no longer available, the invitation has to be sent anew.
How do I gain access to pCon.login?
Whom can I invite to pCon.login?