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 want your users to pay using credit card directly on the form, you can use Paypal Pro, Stripe or Authorize.net, here's a guide to learn more about the payment integrations: https://www.jotform.com/help/323-Mastering-Payment-Form-Integrations-with-JotForm
However, I checked your form and you are using Paypal Standard Checkout in your payment integration, is that correct? Your users can actually pay using credit card even without a Paypal account.
In the Paypal payment gateway, you'll see that option, they are not required to join or signup an account to Paypal but payment will still be processed through here.
I hope that helps.