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.
You do not need to use a textbox to have a signature field on your form. Simply add the Smooth Signature widget to your form and you will be able to collect the signatures of your users. Here's a guide on How to Add a Widget to your Form
You can also check out this demo form to see it in action: https://form.jotform.com/62521436630954
If you need further assistance, please let us know.