JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
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 mean embedding an html code into JotForm, you can do it by getting source code of your form. This is the user guide about how to get source code of a form.
You need to download source code and host it on your server and then you can apply css fixation on it.
However, If you mean to embed a form to your website, you may check below guidance.
Please let us know, if you need any further assistance from our side.