If you don't know how to add credit card on cash app ? No problem . I am here . Secure Cash App has come up with a really cool way to link a credit card on cash app .To link the credit card with your Cash App account, you will need to use your credit card number, expiry date and secret code .Whenever you have to be very careful while entering your card details otherwise your card may stop linking with cash app. However, if there is any problem in linking the credit card, then you will have to contact the customer care center of Cash App.