I need to clone a form with all the Submissions of the main form.

I can only assume that transferring to your account from the main account is not an option for you.

How-to-Transfer-or-Share-Forms-and-Data-with-Another-Account

We would like to apologize for any inconvenience. However, cloning a form will only copy the form itself but not the submissions that the original form has.

You can, however, try to import the submissions from the original form to the cloned version.

First, download the submission on the original form in Excel file

How-to-Partially-Download-Form-Submissions-as-Excel-CSV-PDF

After that, import the data in the Excel file to the cloned version following the instructions in this guide — Import-App-Easily-import-your-Excel-or-CSV-data-into-JotForm