For Visa and Master Cards, the Card Identifier is 3 digit code that is usually printed in the signature panel on the back of your card. It appears immediately after the card number or partial card number.
For American Express cards, the Card Identifier is a 4-digit code that is usually printed on the front of the card. If this is a Corporate Purchasing card and does not contain a 4-digit CID number, please contact your card issuer for CID number.
If you cannot find the Card Identification (CID) on your credit card, please contact your credit card issuer to confirm whether your credit card contains the number, and if so where the number is located.