International iPhone

Hey guys,

I always buy my iPhones in store. But the pandemic has closed most of the Apple stores in my area.

I go back and forth between the US & UK. I am slipping out sim cards from one nation for another. When I buy my phone, they always ask which carrier. When I tell them this, they say that buying from Apple gives you an unlocked phone. And then I re-stress that I don't want an unlocked US carrier phone and they seem to understand.

If I'm buying THAT phone online, which option am I choosing? I just need my seamless international iPhone.

Help?