VPN or Virtual Private Network is a network connection technology in which a virtual subnet can be organized in an existing network.
When you’re at home using WiFi to connect to your router, you’re in your home network. However, if you have a VPN server configured on your router, you can access your home network even when you are not at home.
You can connect to your home printer and print something on it as if you were working from home. It goes without saying that you will also go online as if you were on your home network.