Addition of custom field in Website Shopping Cart

Hello All,
I am new to ERPNext. We are building an e-commerce website. We used the Webshop settings and webpages to design the website.
In shopping cart, we would like to add a functionality of uploading a document before placing an order. This uploaded document by customer should get reflected in backend sales order once the user place an order.
Is this scenario possible?

You can do that by using Web Form but I am not sure about the “Webshop” part.