CVV is an anti-fraud measure being introduced, world wide, by credit companies. It is required that customers enter the CVV number corresponding to their card each time a payment is made and are not present to sign the receipt, as for on-line transactions.
Your CVV number may be found in the following places:
Visa / Mastercard / Diners Club The last three digits of the number printed on the signature panel.
American Express On the front of the card, four digits above and to the right of the card number.
Visa / Mastercard / Diners American Express