From the age of 13, Danes can enroll for the national digital ID system, which can be used for everything from logging into online banking to signing documents electronically and booking a doctor’s appointment. But when they hit 15, all children and their parents receive a letter from the government advising them that from now on, the teenagers will receive their own official communications from authorities which will be sent to them via “digital post”, and they will need digital ID to access it.