iOS 6.1. update had brought many issues to the iOS devices, like the popularly known ones are the Passcode hack and the WiFi problem. But Jailbreaking it pretty easy specially with Evasi0n.
You will need iOS 6 and above for this tutorial to work, but if you haven’t upgraded I would recommend you to avoid it due the the problems people are facing due to the many issues people are facing with it. But if you have installed it I hope yours is going smooth.
Connect your iPhone to the Computer and close iTunes if it’s open.
Download Evasi0n for your operating system, install/ run it (Window/ Mac/ Linux)
Press the Jailbreak button on your computer and don’t touch your iPhone till it’s process is complete.
Press Exit on your on your computer, and let your phone reboot. After the phone has booted open Cydia and let it load and initialize, after it’s done you will be back to the lockscreen, go back to Cydia and you are Done!