How does the security code change for Apple Card purchases?

The virtual card is different from the Apple Card you use with Apple Pay. The Apple Card you use when using Apple Pay has multiple security features that change between each transaction.

The virtual card has a dynamic security code meaning it automatically changes without any user input. Apple refers to it as Advanced Fraud Protection. You can learn more about it in the Apple Support article I linked below.

Depending on the type of transaction, the security changing won’t be a factor. Subscriptions and monthly memberships may use the original security code when each monthly transaction is processed.

Use Advanced Fraud Protection with Apple Card - Apple Support

The phrase used is "frequently with usage and over time " which does not mean daily or on the same day.

It reads, "For fraud protection, your 3-digit security code changes frequently with usage and over time. You can use your virtual card number online wherever Visa is accepted."