Verify the applicant’s identity and personal information. The reason why credit card companies require the household registration book is to verify the applicant's identity and personal information to ensure that the application and use of credit cards comply with regulations and risk management requirements. The household registration book is an important document proving the identity of Chinese residents and contains the applicant's Basic personal information and family member information. For credit card companies, this is an effective way to verify the identity and address of the applicant.