Fortunately, yes, Walmart accepts PayPal payments. On the Walmart website and app, you can pay with PayPal. But if you're shopping in-store you will need to bring a PayPal Cash Card to pay at a physical store. You can pay with your PayPal account by adding money to your PayPal account or using the debit or credit cards that are linked to the account.
But you cannot transfer money to your PayPal account from a Walmart gift card. Even if you have a Walmart gift card, you won't be able to use it to make a payment through your PayPal account.