How does a shul choose its rabbi, its chazan, or even the color of its chairs? Rabbi Shay Tahan explains the Torah's concept of following the majority (acharei rabim lehatot) in community decisions, from the teshuva of the Rosh, the Darkei Moshe and Shulchan Aruch Siman 53.
Who gets a vote? On money matters, those who pay; on other matters everyone, even the poor; and for choosing a rabbi, people who understand Torah (Maharashdam, Divrei Malkiel). Also: the Chatam Sofer on a rabbinic election ruined by bribery, the three ways a rabbi or chazan is appointed, when one person may veto a chazan (Rema, Mishnah Berurah), and why the Mishnah Berurah says a community without a rabbi is a big sin.
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