Credit card field placeholder text

1. What is card placeholder?
2. What is a credit card field?

What is card placeholder?

Placeholder Card is the name of a card with number id 0 , string id PlaceholderCard but no other attributes defined for it (even the card set, card type or cost). As the name suggested, Placeholder Card's main purpose is likely to be used as a placeholder for debugging in development. Advertisement.

What is a credit card field?

Credit card fields are special field types for entering credit card numbers. They provide the following benefits over using normal text input fields: Automatic formatting for credit cards. Card type detection. Automatic value hashing to prevent storing credit card numbers in the WordPress database.