I have read many articles about how to root the android device without having the risk of losing phone software, but the best and easy way to root android phones with just one click is given below
Safely Root Any Android Device
they are the company which provides custom software for each smartphone model. you just have to tell them your android phone model and software version, and the rest is on them.
you just have to connect your phone through a usb cabel, and they will root your device automatically.