American Express card numbers generally contain 15 or 16 digits, which are the unique identification codes of the card and are used to distinguish different cards in the banking system.

The expiration date is usually the month and year on the front of the card, which marks the card's usage period. Once it expires, the card will be locked or canceled. A security code is an additional verification measure, usually a 3 or 4-digit number, located on the back of the card or in the signature area, used to confirm the cardholder's identity and card validity. When making transactions, cardholders need to enter information such as card number, validity period, and security code to ensure the security and legality of the transaction.