If you are asked to use MLA format, you will need to use parenthetical or in-text citations that point to a source on your Works Cited Page any time you refer to information that is not your own idea. This includes when you paraphrase or use direct quotes. Parenthetical citations include the last name of the author and, when available, the page number.
Use the Quick Guide to MLA citations to get started.
If you are writing a paper that requires Chicago Style, you are expected to use footnotes throughout any time you refer to information that is not your own idea. This includes when you paraphrase or use direct quotes. After you use someone's idea, you need to note it with a number after the punctuation. This number corresponds with a footnote at the bottom of the page (or at the end of your paper, if you are using endnotes). The first time you refer to a source, you must write out the full bibliographic information and page number. Subsequently, you use an abbreviated version.