Amazon actually has a useful page with good information for how to sell internationally on Amazon: https://services.amazon.com/global-selling/selling-internationally-overview.html/ref=asus_ags_snav_what The page on Regulations and Taxes.
Please consider joining the Amazon Power Seller Support Group. This group was created to enable Amazon FBA sellers, and those interested in Amazon FBA.
Do I need to send my supplier my product’s UPC code? Unless you intend to sell your product through retail channels outside of.