Callers can’t hear me on phone call

Hi Jojo,

There's a microphone near the bottom of your phone that is usually the source of the problem. Putting the phone on speaker during a call will switch you to the top microphone and if you do that I imagine your caller will be able to hear you then.

First thing to do is to clean the grille at the bottom of the phone. getting it full of dust, dirt or pocket lint can block sound from getting to the microphone and cause the problem you're having. A toothbrush, 90% or higher concentration isopropyl (rubbing) alcohol and some compressed air will set you right if that's the problem. Here's the ports you want to clean.

If that doesn't do the job, your microphone may have died and be in need of replacement. It's not the easiest job on an iPhone, but it's not the worst either. The lower microphone is located on the lightning connector flex cable so you have to replace that whole assembly in order to get a new microphone. Here's the iFixit guide showing you step by step how to replace your charging port assembly.

iPhone 7 Lightning Connector Assembly Replacement - iFixit Repair Guide

One way or another, that should get you fixed up. Good luck and let us know how it goes!