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.
The main account has not shared forms with you yet, but you will need to the main account access to edit the form, otherwise you will not be able to edit it.
Here is a guide that you may share to the main account's owner in order to get the steps to share forms: How-to-share-forms-with-a-sub-account-user