Add Zip Code validation to Wordpress page

I need a zip code validation form I have two delivery methods. Pickup location and Delivery location. When the customer chooses pickup/Delivery location the Zip Code field should validate if the typed Zip Code in the Zip code field exists in the database (our just a simple php/txt file). When the Zip Code does not exist an error message should appear (the same way as when no zip code has been entered). The message should be: “Sorry, but we do not deliver in your area” (see attached screenshot) When in the filed the Zip Code 1238 is noted (so I deliver my products to that Zip Code), it should then be redirected to the order page. I just need a form to add to my page (zip code validation form) with a redirect upon validation