I have always sung in choirs, mostly auditioned ones. A good choir leader should teach you about the right sort of posture, breathing, relaxation, mouth shape etc, as well as learning the notes.
As a teacher I used to lose my voice from time to time. Eventually, after determining there was nothing physically wrong, my GP sent me to a speech therapist, who taught me the same breathing and relaxation techniques that I have since been taught in choirs. I have never lost my voice again. There are times eg if I have a cold, when I avoid singing, but otherwise, it is one of the best things you can do for both mental and physical health.