Your customer cannot register a new card via the Joyn Business App for smartphones.
Your customer doesn’t have a registered Joyn card yet? In that case, suggest the customer download the Joyn app on his smartphone. Registration is very easy and this way, your customer always carries the Joyn app with him!
Does your customer not have a smartphone? In that case, he can register the card in the Joyn Business App on your tablet or via the web page my.joyn.eu/card-registration.