What does it mean to sign a credit card SMS contract with CCB?

You mean to receive a text message asking you to apply for an interview?

If you apply for a credit card through CCB official website and apply for a new card customer, and the Internet Bank Shield has not been verified, you will be sent a text message after the initial approval. Please go to the local CCB outlet for a face-to-face interview, and bring this short message (mainly the application number in the short message) and the original ID card with you. The final audit results will be announced within 2 days after the staff interviews you. If it passes, it will be mailed to you, usually by registered mail, and you will be informed by SMS after mailing.