Purchase of Apps Outside America

I need your help,I’m based in Zambia,Thats a country in Africa then my country is not listed on iTunes and most of the apple country related things. And i have always wanted to subscribe to Apple Music,Buy Apps and other things involving paying on an iphone.Then i have problems of how to get to that stage of doing such,So how can i be able to do that in my country? I have a bank card from barclays bank specifically