When you use the words or original ideas of another person in your writing, you need to document, or give credit to, the sources of those works or ideas. If exact words from the original are used, quotation marks are necessary. If you paraphrase or restate the idea in your own words, quotation marks are not required, but the documentation of the source is still required.
You can refer to Citing Sources page on the Library homepage for help with all citation styles.