In plain words
A virtual private network is a connection that wraps your internet traffic and sends it through another computer before it reaches the website. The network you sit on, such as a hostel router, sees that you are talking to that computer, and not which sites you are visiting. The site, in turn, sees the computer at the far end, not your own address.
It is a tool for a specific job. It does not clean a phone of malware, does not make a login safe if the password is weak, and does not turn you into a stranger on every site you sign in to.
What changes when it is on
Three things change. The owner of the Wi-Fi or the mobile network sees an encrypted stream instead of the list of pages you open. Websites see the address of the VPN server instead of yours. And your connection takes a longer route, which can cost some speed.
Something stays the same: the account you log in to still knows who you are, the browser still keeps its history, and an app can still ask for your location. Picture a sealed envelope inside a courier van. The courier cannot read the letter, but the person it is addressed to still gets it.
A VPN on mobile
On a phone, the tunnel is created by a small app or client that asks Android or iOS for permission to carry all traffic. After you accept, the phone shows a key or VPN symbol. Mobile data and Wi-Fi both go through it. Closing the app can end the tunnel, which is why the battery settings on some phones matter.
Why some cost nothing
A server costs money to run, so a free service is paid by someone. It may be an advertiser, it may be the user's data, or it may be a paying customer who subsidises the free tier. A trial is a fourth route: the service lets you use everything for a fixed period, hoping you will continue. The ten days free here are of that kind, and the link comes from a Telegram bot without sign-up.
For a longer look at what free really costs, the page on free versus paid goes through the checks you can run yourself.
What it cannot do
A VPN does not make you anonymous in any complete sense, and the claim is a warning sign when a service makes it. The provider still sees your traffic's origin and destination, even if it chooses not to record it. We keep no logs, but you still have to trust a statement you cannot inspect, so judge any provider on checks that you can make yourself.
Using a VPN is allowed in some countries and limited in others, and rules change. Whether it is permitted where you are is for you to check; this page does not give legal advice.
A seller is explaining this subject to you, which is a fair reason for caution; each point above can be checked against any service, ours included. The page was prepared with the help of an AI model and its statements were compared with how the service is built.
Questions
Is a VPN just another name for a proxy?
Not quite. A proxy usually forwards the traffic of one program, often without encryption. A VPN client normally covers the whole device, and encrypts what passes through the tunnel.
Does the tunnel survive when I leave Wi-Fi for Jio or Airtel data?
Yes. On a phone the tunnel carries Wi-Fi and data traffic alike, so it works on Jio, Airtel or any other connection that carries internet.
Will the site I visit know who I am?
Not from your address, which shows the far end of the tunnel. If you log in, the site knows the account, and cookies can still identify the browser.
Can the person who runs the Wi-Fi see anything?
They can see that you are connected to a VPN server and how much data moves. They cannot read the pages inside the tunnel.
How do I know a VPN is working?
Compare the address a check page shows before and after connecting. A change in address and country means traffic is going through the server.
Why do I need a client app?
The phone or laptop needs a program that builds the tunnel. This service gives you a link, and a free client turns it into a connection.