Whenever you quote, paraphrase, or even write a sentence that isn't completely your original idea, you need to cite your sources. Because:
A citation is a reference to the source of information you use.
Use the citation style required by your professor as many request the use of a specific citation style. The following links provide reliable, online guidance for citing your work in the text and at the end of your document.
Generally, citation styles are used as follows:
In addition, there are many discipline specific citation styles:
In Microsoft Word 2013 and Microsoft Word 2010, you can automatically create a bibliography of the sources you used to write your document.