By default, the software does not store customer credit card information. This is almost never required anymore when using a live payment gateway, and we STRONGLY recommend against it. The only time this information should need to be saved is if store administrators are processing payment through a manual terminal, or when using recurring products (even then, gateway recurring billing may remove the need for this depending on the gateway you are using).
If you decide to save credit card information, simply set the StoreCCInDB Setting to true.
Credit card information will only appear to admin accounts that have Can View Credit Card #s: checked. You can check this by looking up the account under Contacts > View/Edit Contacts.
VISA PA-DSS requirements state that customers must be able to decline to store their credit card information. In accordance with that rule, if StoreCCInDB is set to Yes, the customer account page will show a Store My Credit Card Info checkbox. If customers uncheck that box and update their account information, their credit card number will not be stored.