Nokia does not officially support rooting and customizing of the device. There are unofficial methods which allow you to unlock the bootloader and root the phones. Nokia is patching these unofficial unlocks from happening with the August security update.
So, you're expected to use your ANdroid One phone as it came from the factory. No modifications possible, which is rather sad.
That's really bad. i root my every phone the day it comes. not good to listen about nokia,