What is the role of VPN servers in the implementation of this technology?

Question

VPN

Hello! I generally understand what VPN is, what tunnels are, I have an idea about tunneling protocols, but I absolutely cannot understand:
1) What is a VPN server for.
2) Where should it be located in the network diagram
3) And for example - what is needed to implement VPN when connecting two devices (PC / mobile phone) and when connecting two local networks.
An example with the implementation of a server on a router (conditionally Microtik) is desirable
.
Thanks in advance for all the replies!

Answer 1

The VPN server is one end of the tunnel.

• On the one hand, your computer is at home, client.
  
• On the other hand, a VPN server is at work behind fences and security.
  

So you raised the tunnel, and sitting at home, leaned out of this VPN server somewhere at work.
Further, if you go to any site, it will see the IP of your work, not your home one. And the villain provider with his SORM equipment, carefully studying your Internet traffic from home, sees only a wired something sent to your office.

Answer 2

Isn't it clear from the title? virtual network. Approximately, like your local from the router.