By default keyboard vibration on typing text is on. It took me sometime to search for setting and making it off. it is annoying having viration while type messages on phone so i made it off.
Follow below steps to make vibration off in your Redmi note 4 having MIUI version 9 with android version 7:
1) Go to Setting and look for "Additional setting" and click on it
2) Inside "additional Settings" look for "Languages & input" and click on it.
3) Now you will find setting for "Swiftkey Keyboard" as below:
4) You will find four options inside Swift key click on "Typing".
5) Inside "Typing" select "Sound & Vibration"
6) Here you will find setting for enabling/disabling "Keypress Vibration". Make it disable if you don't want to vibrate phone while typing text.
It will effect immediately, if not try to restart the phone will stop vibrating while texting.