Tor Browser is a free, open-source browser built by the Tor Project, a nonprofit. It's a fork of Firefox that routes everything you do through the Tor network, thousands of volunteer-run relays around the world. It's built to defend against three things at once: surveillance capitalism, mass surveillance, and censorship.
How it works
When you load a page, Tor sends your traffic through three relays before it reaches the site. Each relay peels back one layer of encryption and knows only the step before and after it, never the whole path. The first relay sees your IP but not the site. The last sees the site but not your IP. No single point knows both. That layered routing is why it's called "onion" routing. Because Tor traffic is hard to block or trace, and can route around blocks using "bridges," it's also one of the most effective ways past censorship.
What it actually hides
The sites you visit don't see your real IP or location. They see the exit relay's.
Your internet provider sees that you're using Tor, but not which sites you load or what's on them.
Trackers and ads are blocked, each site is isolated, and cookies and history are wiped when you close the browser.
It resists fingerprinting by making every Tor user look nearly identical, so you don't stand out.
It also reaches ".onion" sites, services that live only inside the Tor network, so both sides stay anonymous.
Use it right, or it doesn't work
Tor Browser is safe because everyone's copy looks the same. The moment you customize it, you stand out and become traceable. So:
Never install extensions or edit hidden settings (about:config). That is the fastest way to get fingerprinted.
Use the built-in security slider, Standard, Safer, or Safest, to dial up protection, and restart the browser after you change it, or the new setting may not fully apply.
Stick to HTTPS sites. The exit relay can see traffic that isn't encrypted.
Don't log into accounts that identify you. That re-links the browsing back to you.
On your phone, and going further
On Android, use Tor Browser directly. On iPhone, use Onion Browser, which the Tor Project endorses, but know it's weaker: it can leak your real IP through WebRTC, so pair it with the Orbot app. For everyday reading this is plenty, and every casual user makes Tor traffic more normal and weakens the "lists of Tor users" that ISPs and governments compile. If your safety depends on real anonymity, run the desktop Tor Browser, ideally inside Whonix on Qubes OS.
Is it worth it?
For everyday browsing, a private browser like Brave is enough. Tor is for the moments that need real anonymity: sensitive research, reading news under censorship, or breaking the link between who you are and what you look up. Journalists, activists, and people in restrictive countries rely on it. It's free at torproject.org, and unlike a VPN, there's no single company you have to trust.