What does it mean that CCB credit card needs to supplement income certificate when sending text messages?

When you send a text message with CCB's credit card, you need to supplement your income certificate, which means CCB needs you to provide more income proof materials to verify your income. This is because in the process of credit card application, banks need to evaluate the applicant's credit status, repayment ability and income to decide whether to approve the credit card application. Insufficient proof of your income or inability to prove that you have sufficient repayment ability will affect your credit card application results.