If your order total is less than the amount on your Walmart Gift Card, the remaining amount will be available on your card for future purchases.
If your order total is more than the amount on your Walmart Gift Card, you will need to pay for the balance with additional Walmart Gift Cards or a credit card.
For most Gift Cards, there is no activation process required for using your Walmart Gift Card.
For Gift Cards that were purchased as a part of an order of 25 or more cards, or if the total value of the cards in the order was over $250, then the original purchaser will need to activate the cards before they can be used. An email with activation instructions is sent to the original purchaser.