Q: iphone 6s plus problems

Greetings ramana.adla,

Thanks for using the Apple Support Communities!

I understand that you are having an issue hearing audio from your iPhone while on a phone call. Depending on the sound issue, there may be different troubleshooting steps that I would suggest. 

If you are experiencing no sound from the receiver, read over and work through the steps in the following article. 

If you can't hear a person on a call or voicemail or if the sound quality is poor on iPhone - Apple Support

If you are not able to hear audio from the speaker on the iPhone while on a call, the next article’s troubleshooting steps will be appropriate. 

If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

Cheers!