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.
You can use the "Text" tool under the Basic Fields. Just drag it to the work space above the Submit button and then click the "Edit HTML" button. After that, click the "Source Code" icon at the toolbar of the editor. Put the HTML code and then click OK. Here's a screen capture:
If you are trying to insert a Captcha in your form, then please use the Captcha tool under the Quick Fields.
Here's a guide: https://www.jotform.com/help/205-How-to-Add-a-CAPTCHA-field
Hope that helps. Thank you.