When my wife, who is an additional card holder on my Tesco credit card, does a Tesco shop online using our Tesco credit card she has to contact me to authorise it in the Tesco app. As she's not the primary cardholder I understand she can't install the app on her phone. How does she authorise a payment herself? It's a real pain and We're getting to the point of using a different credit card for our Tesco shopping that doesn't make me authorise a payment every time one of us updates our Tesco shop.