I am going to register in some courses and workshops.?

[AM]

In the register form and the payment part, I want to pay it by my credit card (visa card). But there are 19 boxes for the card number on the form, while just 16 digits have been seen on my card. Must I enter CVV (security number behind the card) too in continuous or not?

[Sophie]

yes you need to enter the cvv also, but many sites will ask after the 16 digits entered,
provide the site so that can give more info