Hello Emmamendez,
Thank you for using Apple Support Communities!
We understand from your post that you would like to use the Wallet app to pay for your purchases at stores but it hasn't been working. The feature of the Wallet app that you are describing is Apple Pay. This feature allows you to pay for your purchase using the payment methods you have stored in the Wallet app. This article has information on how you can use Apple Pay which you may find helpful:
How to use Apple Pay - Apple Support
If everything is set up as described in this article to be able to use Apple Pay, but the issue persists, please describe in detail what happens when you try to use Apple Pay to pay for purchases so we can further assist you.
Set up Apple Pay - Apple Support
Best Regards.