How can I download my submissions onto a google drive?

You can download submissions by going to your submissions

then scroll down to the bottom and you will find download as and upload it to your Google drive.

You can also integrate your forms to Google drive so that when the user submits a form it will store the collected submission into your Google drive.

Here is a guide on how to integrate a form to Google Drive.

How-to-Integrate-a-Form-with-Google-Drive