TaiG is a series of tools that provide untethered jailbreaks for all devices on 8.0 through 8.4.

TaiG version 1.2.1 for Windows is a tool that provides untethered jailbreaks for all devices on 8.0 through 8.1.2.

TaiG version 2.4.3 for Windows and version 1.1.10 for Mac are tools that provide untethered jailbreaks for all devices on 8.1.3 through 8.4.

On the TaiG website, scroll down to "Main Versions & Download Links" to select the correct version for your computer and device.

TaiG runs on already-upgraded
un-jailbroken devices.

On Twitter: @TaiG_jailbreak.

Steps: Read the instructions (tutorial) on TaiG's website. Make sure your computer has iTunes installed. Download TaiG. Open it, plug your device into your computer, and follow the instructions.