How do I change the background color of the "Thank You Page" to white?

https://form.jotform.us/71374135388158

You have a couple of options here:-

1. Use custom CSS

How to Inject Custom CSS Codes

.thankyou

{

background-image: none;

}

2. Create your own thank you page. Then use the redirect to external link option.

You can even post submission data to the thank you page:

How to Post Submission Data to Thank You Page

@mlangbuff 

I presume this is resolved now upon checking your form.

If not, please let us know. We'd be happy to help.