PHP切换使用表单促销代码 - 在Wordpress中

I have a simple form. I need different promo codes to redirect you to different pages. Example: 1234 will send you to example.com. 2323 will send you to newwebsite.com. I understand how to do this using a form and php, but I need the client to be able to enter the codes and redirects themselves. There didn't seem to be any plugins that did what I need. I use gravity forms, but that would still require the client to edit the template file. Here is my code:I have a simple form. I need different promo co