How do I upload an invoice to a business customer? Or is Amazon already doing it for me?

I’ve been selling on Amazon through FBA for years, but decided to do FBM for a few products.

I see there is an invoice defect rate that I have to be aware of, and this involves uploading invoices to business customers. I see there’s an option for Amazon to issue the invoices themselves, I am not sure how to do that or if it’s already set. In I am Canada and have added my tax number, but I do sell mostly in the U.S.

However, when I try to see if I can even upload an invoice there doesn’t appear to be an option in the orders page. I have options to refund the customer, contact the customer etc, but nothing to upload an invoice. I do see it says that “Tax Collection Responsible Party: Amazon Services LLC”…would this be an indicator that Amazon has already issued the invoice?

When I look at the order under payments, I see the business customer has already paid.