Jailbreaking is a terrm used to adaprt Apple devices. Rooting is the Android equivalent and one way of doing it is to download KingoRoot to your Windows PC and connect the phone with a microUSB to USB cable.
Then, in Settings>More tap Build Number seven times and you'll be told you are now a developer and the menu Developer Options is added to the list. Go into that and set the USB setting to Enable Debugging.
At that stage, you can run KingoRoot and the process takes about ten minutes. There is a possibility that the manufacturer or a service provider has messed wih the standard software to prevent rooting.