To make online purchases with a Visa debit card, enter the debit card information on the payment section of the online retailer's checkout process, according to Justin Pritchard for About.com. The retailer processes the order as a credit transaction, but Visa deducts the amount from your checking account and does not charge any interest.
Shopping online has security risks, and Pritchard recommends using credit cards instead of debit cards online if you want to minimize the possible impact of fraud. If a thief gets your debit card information, he can make purchases using your money. With your credit card number, he can make purchases using your card issuer's money. Although you can dispute unauthorized transactions on both debit and credit cards, it is more convenient to keep your own money instead of waiting to get it returned.
Visa offers several security features for its debit cards, including a zero liability policy, fraud monitoring and identify theft assistance, explains its website. Its zero liability policy protects cardholders from unauthorized transactions, as long as the cardholder meets Visa's criteria for the policy, such as reporting the fraud within an appropriate time period. Visa debit cards also have three-digit security codes on the back that provide additional protection for online and phone purchases.