International move

So I’m moving to the US at the end of the month. However I currently have a tab on my phone that has yet to be paid off. I was just wondering about my options. I had thought about just closing my plan and continuing to pay off the tab til it’s all paid off. But I don’t know if my phone would be compatible with a US phone plan. I know some phone are “locked” to the country they were sold in so I was just wondering about that. Also I didn’t know if it’s possible to close ur plan while u have an active tab on a phone. With all that said what would be my best option. Thanks