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.
as a percentage? instead of a flat rated number?
You can add it as a shipping fee. That's possible with any of the payment tools you may want to use.
Example, if you want to use Paypal field, just drag it to your form, create your products, click next until you reached the other options section. Click shipping if you want to add a shipping fee. Unfortunately, shipping does not support percentage rate, only fixed price.
However, you may find this old method helpful specifically for the Paypal Standard. This has percentage rate support. https://www.jotform.com/help/188-How-to-add-Shipping-to-your-Paypal-standard-account
If you have further questions, let us know. Thanks!