HOW TO ROOT INFINIX NOTE 3 & NOTE 3 PRO

Granted you have successfully installed TWRP Recovery after going through the detailed instruction on how to install Recovery image via Sp flashtools to your Infinix phone, now do the following:

1. Boot your Infinix phone into TWRP recovery mode (by Holding the Vol. Up + Power button at the same time for 5 seconds).
2. In TWRP recovery mode, Choose "Install zip". 
3. Then navigate to the location you placed SuperUser v2.66.zip file and proceed to install
4. After installing SuperUser.zip, reboot your phone

That's it, you have successfully rooted your Infinix Note 3 & pro version smartphone. To verify if its properly rooted, goto Google playstore and download "Root Checker.apk" to verify.