VPN as you know it stands for Virtual Private Network. The name pretty much says it all. A private network obtained through transforming a public IP virtually.
Here is how it works!
Once you connect to the Internet, your ISP(Internet Service Provider) receives the request to help you redirect to your intended website.
VPN redirects your Internet traffic through a remote VPN server, this way it provides you with a different IP address, other than the one that your ISP provides. There onwards it encrypts all of the information that is sent or received. With a VPN on, all the data you send and receive travels via an encrypted tunnel so that nobody can steal your private information by monitoring your online activities. Ultimately adding an extra layer of security to your data!