1, the general credit card center will inform the registered letter code by SMS;
2. If not, call the credit card center of the issuing bank to check the registered letter number of the mailing credit card;
3. Visit the website of China Post;
4. Or call the postal customer service hotline for inquiry;
5. After sending a registered letter, most banks will inform the registered letter number by SMS to facilitate the inquiry;
6. If you need other express delivery, please contact the bank credit card center in advance and pay the postage in 20 yuan.
I hope my answer can help you.