Does anyone know what is the agreement between for delivery post for each other?

Question

For example, New Zealand Post and China Post, when NZ post delivery mails for China Post, and you know people over in China will pay for the postage and NZ Post will delivery mails, does China Post pay NZ post anything, vis versa or between any other countries. Or it might be free by an agreement between all countries or maybe just a contract. I'm interested this if anyone can help. Many thanks

Answer 1

no because the market difference 1.6 billion chinese posting things or just a handful of new zealanders