How to unlock US factory unlocked M7

I am interested in acquiring a second phone and I always had a soft spot for HTC ONE
(I am not a android user and never owned one)

I found a very interesting deal on amazon.com (HTC ONE M7 US Factory unlocked) for 110$

However I don't reside in US so I need to use a non us carrier that supports 2G, 3G and 4G (magticom.ge)

So will I be able to use this phone out of the box or I need to fully unlock it first.

If I need to fully unlock this phone is there a free way to do it or if there isn't one what service can I trust ??

Thank you in advance