"Google Spreadsheet Form" is a Opencart extension.
This extension will help us to store our form submission in Google spreadsheet file.
Unlike regular forms, it will store our data on spreadsheet instead of Mysql database.
We can easily organize all form submissions in single spreadsheet.
1) "Google Spreadsheet Form" Opencart extension.
2) Google account authorization for spreadsheet API (Support will be provided for purchased customers, Gmail account required).
For more details checkout this extension on Opencart market place