Q: Bugs in sms of IOS 9.2

Hello there, imranfromkochi.

It sounds like you're having issues with the Messages app quitting unexpectedly. Although this Knowledge Base article was written for apps installed, but the initial steps are still practical for troubleshooting:

If an app you installed unexpectedly quits, stops responding, or won’t open

Restart the app

Close the app and open it again.

Restart your device

Turn your device off and back on.

Check for iOS and app updates

Make sure that you're using latest version of iOS.

For some additional information on issues with Messages see this article as well:

If you can‘t send or receive messages on your iPhone, iPad, or iPod touch

Thanks for being part of Apple Support Communities.

Cheers.