What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
If you would like to get that sample "Thank You Message" with close button on this form http://www.jotformpro.com/form/40504759640960. You can use this guide to clone that form and check its settings: https://www.jotform.com/help/42-How-to-Clone-an-Existing-Form-from-a-URL.
For a quick guide, you can check the screenshots below.
1. Navigate to "Thank You" option in toolbar.
2. Inside the "Thank You" page wizard, you can add an image with a hyperlink.
3. You can also style it using HTML codes.
I hope this helps.