The CVV/CVC code (Card Verification Value/Code) is located on the back of your payment card, on the right-hand side of the white signature strip. For Visa and Mastercard it is always the last 3 digits.
Copy the CVV/CVC from the back of your payment card and continue with the payment.
Visa uses the term CVV or CVV2, Mastercard uses CVC or CVC2.
Security
These days it can be easy to obtain someone else's payment card details — in brick-and-mortar shops, for example, security cameras record us during almost every payment. This is one reason why the CVV/CVC verification code is placed on the back of the card, where it provides a basic security measure. The CVV/CVC code is therefore required for all online payments, where the payment card is not physically present and the cardholder's PIN cannot be requested.

