It is one of the most common words in English. "People" has a regular plural "peoples". We can talk about "the French people" or "the Italian people", or "the peoples of the world", referring to various ethnic or national groups. However, "people" is also unique in English insofar as it acts as a suppletive plural of "person"; an alternative analysis however is that this is a collective noun.
It can abbreviated "ppl" in Internet shorthand.
It also forms numerous compounds, e.g. "people person" - being a people person is useful in teaching.