Q: I can not hear well on my iphone 6

Hello NSérgio,

Thanks for posting your question. I see from your post that you’re not able to hear very well while on a phone call with your iPhone. I’ll be happy to get pointed in the right direction.  I have a few recommendations. The following resource has some great steps, though I believe you have tried at least one of them already: 

If you can't hear a person on a call or voicemail or if the sound isn't clear on your iPhone - Apple Support

Also it would be helpful to make sure you have a back up of your iPhone, you can find the instructions for that here:

Import photos and videos from your iPhone, iPad, or iPod touch

How to back up your iPhone, iPad, and iPod touch - Apple Support

If the steps in the first article don’t help. I recommend restoring your iPhone as new as described in the next article. Once you have it restored, test to see if you are able to hear better. Restoring as new will help isolate the issue to either a software or hardware issue.

Use iTunes on your Mac or PC to restore your iPhone, iPad, or iPod to factory settings - Apple Support

Hope you have a great rest of your day!