Will screen sharing work across different ISPs and over the Internet? I’m just beginning to learn the use of screen sharing between two Macs.

Today I’ve successfully implemented it with two different computers on my desktop, using the "Sharing" section in System Preferences.

What I wonder about now is, once those two computers will be in places very far from each other and using completely unrelated internet providers, will the screen sharing feature automatically work the way it does when both computers use the same internet provider ? Or need I specify some data about servers, ip addresses or something like that to one of the computers ?
This question is quite broad, and there is no succinct answer. Many ISPs have filters on their networks and do not pass all IP protocols transparently.  I have experimented with Chrome Remote Desktop, however, and it seems to be work very well. I can access to my home iMac (on Verizon FiOS) through my school's firewall without a problem, and with my iOS devices, too! You might want to experiment to make sure it does what you need.