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.
Unfortunately, it is not possible to achieve your requirement. When you integrate you form with a google spreadsheet it creates a new google spreadsheet in your google drive. Your form and google spreadsheet has a one to one relationship and all data of the respective form will only go to one google spreadsheet. There is no way available for multiple form's data to be saved in one google spreadsheet.
The only possible option is to download the submission data of all your forms and manually merge/copy them in one spreadsheet.
Hope this answers your query.
Do get back to us if you have any questions.