As for Contact Form 7 to validate field values from a pre-prepared base?
There is a manually generated database of promotional codes that are printed for distribution offline.
It is necessary to form checked that you entered the correct promo code in the appropriate field by comparing with the list. If the code is entered correctly, the form with all the data is sent in the mail.
How to create a form, add fields and send email - this is clear.
The question is how to add field codes to valderrobles according to a given list?