ID cards are printed cards with a QR code that has an account attached to it. You can give the user a paper ID card, if they do not have proper devices to use mobile version.
You can also hand over an empty card, ask the new user to scan the QR code and they can simply fill in their account information and have a working youth card account!
ID cards can be used when registering school classes to use youth card or for promotional purposes.
You can attach the user to different groups while creating the ID card.