USA iPhone in other countries

Buying an iPhone in one country to use in another country can have many disadvantages:

Make sure it will work in your country.--> 5G and LTE. Find the iPhone that’s right for your country or region. - iPhone - Supported 5G and LTE networks - Apple

The iPhone 14 series devices sold in the US do NOT have a physical SIM slot. Check if there's a carrier in your country that offers eSIM service:

Find wireless carriers and worldwide service providers that offer eSIM service - Apple Support

Warranty restriction! - Legal - iOS Warranty Document Us - Apple - "IMPORTANT RESTRICTION FOR iPHONE, iPAD AND APPLE TV SERVICE. Apple may restrict warranty service for iPhone, iPad and Apple TV to the country where Apple or its Authorized Distributors originally sold the device." <-- The warranty does not outright deny warranty coverage in other countries but there are many limitations to the effect Apple almost certainly will refuse to do repairs under warranty or even repairs at all except in the country of purchase. The device would have to be sent to a friend in the country of purchase to handle any repair claims because Apple will not handle international shipping.

If you purchase a “Select Carrier Later” device directly from Apple, it most certainly will function to some degree, but …

Some things to consider:

A device purchased in U.S. will only carry a U.S. warranty.

A U.S. spec phone might not be able to utilize all of the freq bands available on Ukraine’s networks.

A U.S. spec “14” will not have a nanoSIM tray. (It’s eSIM only)

For these reasons, it’s always advisable to purchase a phone in the region of it’s primary usage.

It would help if you said which model phone.

Warranty may be a big difference. If you take it to another country and something goes wrong, Apple in the other country may well say you have to take it to the US to get it repaired. And no, Apple doesn't do international shipping.