Shaliach Tzibbur

Shaliach Tzibbur (Hebrew: שליח ציבור) , literally means the messenger of a congregation in a public prayer, is a Jewish prayer leader in the Synagogue also known as Chazzan (Cantor).
According to Jewish tradition , any Jewish male over the age of 13 can function as Shaliach Tzibbur. However, the role is usually given to the person with the best voice and the best knowledge of the Jewish prayers.The Jewish prayer services are collected in a Prayer Book called Siddur.

In the Talmud , the Shaliach Tzibbur is referred to as the one “who passes before the Ark”.
In rabbinic times, many people were unfamiliar with the Jewish prayers. Usually there was one person recites the prayers aloud with the congregation responding to his benedictions with “Amen”. Even after the wide dissemination of the Siddur, the institution of the prayer leader was continued, so that the prayers were then recited by both the congregation and the reader.

According to Shulhan Arukh (Orah Hayyim, 53) Chazzan should be a person without sin .He should be free of rumors that he had a bad reputation in his youth. He should be a modest man and acceptable to the people. If such a person is not to be found, the man chosen should be the most pious and learned in the congregation.

Credit:
myjewishlearning