Warranty and technical service

Hi! I'm Natalia and I live in Medellín Colombia.

In the next two week I'm planning to buy a new Iphone in Boston or Chicago's Apple Store. I would like to know: If I buy this phone in any of this two places, Will I have warranty coverage and technical Service (in case of damage) in Medellin Colombia in what Store authorized by you? Can you explain to me how this works in this cases?

Thank you for your attention and let's keep in touch

Regards, Natalia