In the "My data" section, you can see your name or the name of the business, the sourcePIN for the business (entry number in the Commercial Register, Central Register of Associations or ERSB [supplementary register for other parties affected]) for which you have opened My Mailbox and the status of your registration for electronic document delivery. If a mandate to represent someone else has been activated, this is also displayed here.
If you are only registered with My Mailbox to receive documents not requiring proof of delivery (for example because data have been transferred from another system), you will be offered the option here of also registering to receive documents requiring proof of delivery electronically. To sign up and receive documents requiring proof of delivery (cf. RSa letters), you have to log in using your mobile phone signature or Citizen Card.