How to properly route windows application traffic through vpn?

Question

VPN

I am slowly studying networks and the question arose - how do VPN services direct traffic of 1 (or several) applications (online games, instant messengers, something else) through themselves? I understand that there is a route in windows, but I'm not sure how exactly the interaction between the vpn client and route is implemented.
if ip addresses are known, then the vpn client simply enters the desired rule in the route, and then simply deletes it?
what to do if it is not known (or they are constantly changing) to which ip the program connects?

Answer 1

How to properly route windows application traffic through vpn?

What does it mean is not clear.
Route traffic is very simple - if you need to route all traffic, make the gateway on the VPN network the default gateway.
If not all - just register the route to the VPN network for the necessary traffic.