Q: Letters I and K on the keyboard they don’t work when i pressed them

Hey there swagatam,

Welcome to Apple Support Communities.

From what I gather, there's an issue tapping specific letters on the keyboard of your iPhone 6 Plus. Try taking a look at the article linked below and try running through the general touchscreen troubleshooting tips that it provides.

If the screen on your iPhone, iPad, or iPod touch doesn't respond to touch - Apple Support

Also, this article provides some general keyboard related troubleshooting tips:

Get help with the keyboard on your iPhone, iPad, or iPod touch - Apple Support

Ciao.