In the grey area immediately below the logo and above the list of messages, you can see the name of the person or business for whom My Mailbox is currently displayed. If you are authorised to receive messages on behalf of other people or businesses, this is where you can switch to the view for the person or business which you are representing.
When you click on the "Select representation" button, a new window comes up where you can see the bodies which you are authorised to represent. The user in whose name you have currently opened My Mailbox cannot be selected again and is therefore greyed out. If you click on a different person or business which you are authorised to represent, that window closes and you can then use the mailbox in the name of the person or business that you selected.
Note: This function is only available on the citizens' service portal oesterreich.gv.at and in the "Digital Office" mobile app. If you are not authorised to represent anyone else, this button is not displayed.
Mandates granted between private individuals can be entered in the online mandate system, and mail mandates for businesses can be registered on the business service portal.