Commas are an important punctuation mark that indicate pauses and clarify meaning. They help readers understand which words go together and identify the most important parts of sentences. Commas are used in dates, addresses, lists, sentences with independent clauses, sentences with introductory elements, additional non-essential information, absolute phrases and locations, to separate adjectives, within quotes, to express contrast, and to avoid confusion. The document provides examples for the different uses of commas.