Pre fill customer name and other fields from google sheets or contact info

Is there a way to fill in the form based upon external data?

So if I put in the customer name it looks up their email address in a database such as google sheets, mailchimp, etc.

Unfortunately, this is not possible in the form builder. If you wish to do this, you need to get the source codes and incorporate the custom functions. You are then required to embed it as a modified source since there is no way you can import it back in the form builder.

To get the source codes, follow the steps on this guide: https://www.jotform.com/help/104-How-to-get-the-Full-Source-Code-of-your-Form.

As for the scripts, I don't have it but I'm willing to find one if you need to.