When i am talking on the phine what hole does my voice go through?

Mauricio,

Get help with the microphones on your iPhone, iPad, and iPod touch - Apple Support should help you troubleshoot this issue.

One of the items listed states: "Remove screen protectors, films, or cases that cover the microphone, iSight mic, or iPhone receiver."

With every iPhone, if holding it upright in front of you, with the screen towards you, the main voice microphone is the small hole on the bottom at the left, next to the headphone jack. There is also a noise canceling microphone on the back by the camera LED flash, and if that is covered, your voice will sound muted to callers.