Network question. What should be the network?

Question

Computer networks

Here is a program on one 1PC and on the same program on another 2PC. One person wrote or changed something in it (that is, he opened it there, added an entry in the program) (Not in the code) on 1PC. And another user, a user on 2PCs, saw this change. Can this network be local or is it necessary to do it all through the Internet? How easier?

Answer 1

Can this network be local or is it necessary to do it all through the Internet? How easier?

Not necessary. It doesn't even matter, the application program is the highest OSI layer, they don't care what network it is.
Which is easier depends on the situation. If both clients have two white IPs, then working through the Internet is easier, and for the local network it doesn’t matter if there is an Internet. But again, it doesn't really matter.