The purpose of Virtual Private Network (VPN) is to provide online privacy so that hackers or other fraudulent elements should not be able to attack the user. How VPN will be able to carry out that mammoth task of protection is answered through encryption mechanism. It will provide complete shadow from the outside and no one will be able to find out what the person inside the VPN is doing and all his traffic will flow as usual. When we are working in a public network then we are open to outside cyber criminals who are always on the prowl to cheat us by doing theft of our sensitive information like password and other equally important entities. The data stolen from a VPN network would not be of any use as its decryption will be impossible by a third party. What the outsider will see is only the IP address of VPN as it would mask ones actual IP number. VPN will not only protect our data but also block the malicious sites in sending cookies or malicious codes to our place.
The VPN network achieves all these functions through its servers and will send the data of the user in an encrypted form to the website where the user wants to visit. The website will see the VPN server and not the user. So, it is now disabled to track the user and not able to do any mischief with the user. A good VPN provider will have many servers across the world and they will go on updating their IP address and websites will not be able to track them and take some advantage in doing wrong things through them. Anyway, using VPN is a legal thing in most of the places though in some countries like China and Iraq it is not allowed to be used by the private users.
Another important thing is that we have to go for a reliable and trusted VPN service and must know its credentials. A good VPN service provider will give many facilities to its customer. Some of these are - no log policies, DNS leak protection, IPv6 leak protection, 256 bit encryption, auto kill switch, good customer support, multiple device support, WebRTC leak protection etc and one has to confirm them from the offer document of the VPN service provider.
It is not that VPN is the ultimate guard in the net. There are some downsides of VPN also. It will affect the speed of the connection as it has to do many additional things and may be travel more electronic distances as server may be anywhere in the world. Another thing is that some smart websites even block some of the VPN services on one pretext or other. Some international payment gateways like Paypal can create problem in financial transactions if one is connecting ones connection through VPN.
There are many good VPN providers and some of them are CyberGhost, ExpressVPN, Plavpn, Surfshark VPN, IPVanish VPN, VyprVPN, Hotspot Shield, PrivateVPN, NordVPN etc.
Knowledge is power.