How to Root Any Device

That said, root access is generally the first step on your journey to device modification. As such, root access is often used to install custom recoveries, which then can be used to flash custom ROMs, kernels, and other device modifications. Root access also enables users to install the powerful and versatile Xposed Framework, which itself acts as a gateway to easy, non-destructive device modification.

Source: www.xda-developers.com