how to buy iphone in USA using credit card issued from another country

Careful if you are buying a phone in the U.S., because the warranty will only be good in the U.S. If you take the phone to another country, you will have no warranty.

It is always best to buy a phone in the country in which it will be used most of the time.

You can not but online using a foreign credit card.

You should be able to make the purchase in a physical Apple Store.