Main Features:

• Block Trackers: Tor Browser isolates every site you visit to avoid third-party trackers and ads following you. What's more, when you browse, it automatically clear cookies.
• Defend Against Surveillance: Tor Browser protects you from revealing what websites you are visiting. Those monitoring eyes can only see that you're using Tor.
• Multi-Layered Encryption: When you use Tor Browser, your traffic is relayed and encrypted three times as it passes over the Tor network. The network is made up of volunteer-run servers known as Tor relays.
• Search Freely: In the help of Tor Browser, you are free to access websites your local internet service provider may have blocked.

More:

One of the most concerned questions about Tor is: is it illegal to use? Nope, not in the least. Tor is just a browser and only has advanced capabilities to protect your own identity and activities, which is not illegal by any definition in any country.