want to know How can I register while I'm out of New York State?
Yes
You can request a New York State registration and a certificate of title by mail from outside New York. You should send these items to a local DMV office
and how do I do if I travel and my registration expires?
must determine if the other state can issue a "in transit" permit, which allows you to transport a vehicle to New York so you can register it
and do I need to submit proof of ownership?
yes and proof of ownership must be original
And what else should I deliver?
must provide proof of New York State auto liability insurance
and if My vehicle comes from another country. What I need to do?