Shipping document from Italy to US


Hello everyone,
I packed my products and I’m ready to ship. I’ve got the FBA label which is on the packages.

Which shipping documents are required? I’m sure UPS will ask for something and I know of course that products must pass the customs both in Italy and US too but I don’t know how it works with Amazon. Do I have to release an invoice? To whom it has to be addressed? Or if it is “only” necessary to prepare a Proforma Invoice? Can someone please help me on this?
Thank You very much for helping.


Would also like to know this so if @Italian_taste found out, or if anyone knows, I would love to hear the result!

Another European seller wanting to ship into US FBA.