How to Flash Custom Recovery and Root Redmi Note 3G/4G

Before we Start Rooting process doesn't void your warranty but flashing custom recovery do.
Proceed at your own risk.
Works with MIUI 7 only
First of download Files given below
For Note 3G
1. Recovery
2. SuperSu
For Note 4G
1. Recovery
2. SuperSu

Flash Recovery via updater app
1. First of all Download this file recovery.zip
2. Move it to internal Memory.[Not in any folder]
3. Open updater app in your mobile. [Press 3 Dots in right hand side corner]
4. Choose Select update package
5. Scroll Down and Select recovery.zip
6. Select update and start update.
Flash Recovery SuperSu [Get ROOT ACCESS]
1. First of all Download this file supersu.zip
2. Move it to internal Memory.[not in any folder]
3. Open updater app in your mobile. [Press 3 Dots in right hand side corner]
4. Choose Select update package
5. Scroll Down and Select supersu.zip
6. Select update and start update.
7. Wait

Credits:
XDA developers Forum