When I send or receive a call, the person on the other side can't hear me When I make a phone call, people on the other tell me that my sound is like I am speaking in a huge water pot or something like a pot.

I have a Samsung Galaxy S3.
Check the microphone of the device. On the S3 I believe it is the little hole on the right side of the charging port.  I have seen this issue numerous times and on occasion, it's a clogged or semi clogged mic port. If the issue is intermittent, the aforementioned possibility is less likely. Other times it is network related, app related or, worst case, a failing microphone.