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.
I'm assuming you already have the image link. You can paste it to Button Image to change the submit button.
In the Form Builder, select the submit button field. After that, click the Button Image and paste the image link.
Here's the result:
Hope that helps. Let us know if you need any further help. Thank you.
Your question about the border has been moved into a new thread. Here's the link https://www.jotform.com/answers/894633. Will address it shortly.