Adding a Form to the Product Shipped E-mail

Site URL: https://magnolia-sprout-wnbn.squarespace.com/config/commerce/checkout

As part of the service we provide, the customer must send us some digital information after the order is completed.  Sq.Space thought they could complete this through a the product additional information form, but that form is not operational after they paid for the item.  The customer cannot submit their digital information until after the service paid for as we have to confirm that they have the appropriate credentials. 

So, we've been brainstorming workarounds.
Can the submission form be sent with the  "order fulfilled" notification as that has all the customer/order/service details on it?  And if there is a way to get that back to me. 
Another alternative would be to add a free product to their account/cart which is basically just the submission form.  In either case, I would like this to be pre-filled with their order, account, and service items.  Each service item does require a digital response and must be tied to that service.  
Is this something that Google sheets can work with?  But . . . I was really hoping to direct them back to the website for all order information.

How do you handle customer follow-up?

I really could use some help on how to get this done as I do not want to manually do this for thousands of data entry points on an excel sheet and manual customized e-mails.  HELP!