How to uninstall system apps on Android?

For low memory device there is need to uninstall some system app which are not in use or not require. So, to uninstll system app the device must be rooted. How to Root Android?
then install an app named Uninstall expert Play store Link. Lots of app link this in play store. i choose this coz of small size , easy & fast.
                 

1. Launch app
 

2. Swipe to system apps
                                   

3. Tick in box which you want to uninstall. & Uninstall it
                                                    

comment for any assistance...