1. primary and secondary card association: the primary card holder can add secondary card holders, and the secondary card holders can use the credit line of the primary card holder for consumption, and the bill and repayment responsibilities are borne by the primary card holder.

2. * * * Credit line association: Two or more credit card holders can enjoy line association through * * *, that is, multiple credit cards can enjoy the same credit line. Each cardholder can use the * * * credit line for consumption, and the bill and repayment responsibilities are borne by their respective cardholders.