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 can add quantity property by going to the Payment Tool Wizard that you have added to your form.
Please use the Next button until you reach the Products listing page. On it, you should see the Add New Option when you mouse over the product. By clicking on it, you can add your product quantity.
Your form will now have a quantity property for the product.
To give you a better understanding of the payment / order forms, I would advise you to please take a look at the following guides:
Please let us know if you need further help along the way, we will be happy to assist you.