I posted CCB below, and other banks are similar.

Friends who have done credit cards should know that the main cardholder can apply for a supplementary card, but there are strict rules for applying for a supplementary card. Taking construction as an example, this paper introduces how to handle the supplementary card of CCB credit card.

CCB Credit Card can apply for up to three supplementary cards for each main card. The main card holder has the right to apply for cancellation of the supplementary card at any time.

All transaction funds of the secondary card and corresponding interest and expenses are credited to the account of the primary card, and the cardholder of the primary card bears all repayment responsibilities; The main cardholder and the supplementary cardholder with full capacity for civil conduct shall be jointly and severally liable for the debts owed to the bank, while the supplementary cardholder with limited capacity for civil conduct shall only be liable for the debts incurred by the supplementary card held by him.

Two, the construction bank credit card supplementary card application need to provide information.

The main cardholder of CCB personal credit card can download the application form online or go to the outlet to collect it. Please fill in the field information of the main card number and the secondary card, and the cardholder of the main card and the cardholder of the secondary card sign the signature fields of the main card and the secondary card respectively. In addition, you need a copy of the cardholder's ID card, and then submit the application form and related materials to CCB outlets.