Go to Settings > Security (or Lock Screen and Security) and toggle on Unknown Sources to allow the installation of APKs from outside the Play Store.
If successful, you will see a "Rooted" message. You can confirm this using an app like Root Checker . Critical Safety and Security Risks kingroot android 601 install
It remains popular because it does not require a PC (though a Windows version exists) and aims to bypass the need for a custom recovery like TWRP. How to Install and Use KingRoot on Android 6.0.1 Go to Settings > Security (or Lock Screen