It is possible for Walmart to refuse to accept the return of an item if it does not have a receipt. Walmart generally accepts returns on almost all items, but they may reject returns on certain items.
It is best to keep all the receipts that you received when you returned items to Walmart, as they will be necessary in order to receive your refund. Retaining your receipt helps make returning the item to Walmart easier; keeping your receipt helps you receive a refund faster.
Walmart generally accepts returns that are sent to it without receipts, but there are some exceptions to this. It does not matter if you have a receipt or not, you must return your merchandise within Walmart's standard return policy.