SuperSU is possibly the best app to get root privileges and one of the best available on Google Play. This fantastic tool has just been updated to version 1.10, which adds support for multiple users, support for x86 devices and more!
When Google launched Android 4.2 with multi-user support, many asked: how can handle root access secondary user accounts? The answer given at that time was: we can not. Apps like SuperSU simply will not work in accounts other than the primary user.
Phoneia.com (February 23, 2013). SuperSu is updated and includes support for multiple users and x86. Recovered from https://phoneia.com/en/supersu-is-updated-and-includes-support-for-multiple-users-and-x86/