The main card is the card that the credit card account holder applies for, that is, he uses his own card; the supplementary card is the card that the main card owner applies for use by his relatives, such as parents and children, who use it The bill is repaid by the primary cardholder, and the primary cardholder can also see it. Principal cards and supplementary cards belong to the category of credit cards among bank cards.

The relationship between the main card and the supplementary card is: they share the same credit limit, that is, an "internal bank account" for management. The consumption limit of the supplementary card holder belongs to the main card holder. Generally, only immediate family members can apply for supplementary cards. If the money from the supplementary card is not repaid by the due date, the responsibility still lies with the main card. If the credit of the main card is damaged, the personal tax system will record this bad record on the main cardholder.

Reference Credit Card-Baidu Encyclopedia