Upload a customer file related to a product.

In the past in product atribute it was posible to select.
A customer could then upload a file example a picture to print on a tshirt.
Now in the version 3.9 I could nott find it ?.

You need to "File Upload" in Control type at add attribute to product.

http://admin-demo.nopcommerce.com/Admin/Product/ProductAttributeMappingCreate?productId=45

I enabled File Upload at checkout page, but I don't want to force customers to upload an image in order to complete the check.

Instead, I want to allow customers to upload an image later after they complete the checkout, is there an available function or plugin to support it?

What I want is when they go to "My Account" => "Orders" => "Details", there is a File Upload button in the Order Information Page.