thanks for the reply. well, what do you mean by reachability? I connect to him using any-desk or similar software. but to set up this VPN I think I need a static IP right? is it possible with any kind of software to only use the usual IP? otherwise, I am thinking of buying a VPS and setup VPN on it and not bother my friend at all. what do you think?

Hello,

To set up any type of service , your friend computer should have a public ip that is known by you and vice versa.

Do you have established rechability between the two???