Your outfitter/Taxisermist.shipping agent should help you with this. Different rules for different countries and animals. Generally speaking your trophies will be dipped and packed and shipped to your taxidermist. The hides and horns will have to be completely dry. They may need special permits for export and import. Your Taxidermist or Shipping agent will have to present your shipment for Inspection when it comes in.
Don't have the taxidermy done overseas, it's cheaper, but cost more to ship and if you don't like it you'll have to figure out how to get it shipped back if you can.