The document discusses the proper uses of apostrophes, which include forming possessives of nouns, showing contractions of words, and making some plurals. It provides examples for each use, such as forming possessives for singular and plural nouns like "the mayor's car" and "the Kennedys' house." It also discusses forming contractions in verbs and omitting letters, like "I'm" for "I am." The apostrophe is used carefully to avoid confusion over meaning.