Why my phone not work
my phone does not work in another country and buy it today
Even if you could get it to work in another country, you have made a mistake. People should purchase iPhones in the country where it will be used. Otherwise, Apple may well not be able to service the iPhone, and AppleCare would not be honored.
Perhaps you purchased a locked iPhone. Or perhaps it is not compatible with the cellular carrier's frequencies used in your country.
Refund it if you can, and purchase in your country.