VPN establishes an encrypted tunnel between the user and the server.
Once the user is connected to a VPN, their real IP address is replaced with the server’s IP address, and they’re able to access the website.
First, the VPN goes to the server through a tunnel and then forwards the requested website.
To the proxy server or the router, this traffic appears to be the heading of the VPN but not the required website or URL. In such a way, it doesn’t get blocked by filters.