CVV2 stands for Card Verification Value 2 and CVC is short for Card Verification Code (you can also encounter other acronyms that usually define the same thing: CVV/CVC2, CID , CVD , CVVC ).
The CVV2/CVC verification code is located on the back of your Zumo debit card and acts as a basic security feature. The CVV2/CVC code is required for all online payments where the card is not present and no PIN code can be entered.
With your virtual card, you'll find your CVV2 value in Settings > Zumo Account > Zumo Card. Then tap the eye icon in the top right corner of your card to reveal your CVV2 value, next to the expiry date.