A documented paper requires that you identify the sources you have used to write your paper. This list of "works cited," comes at the end of the paper. Formatting this list is difficult. Fortunately, there are some marvelous online tools that will do this for you. Consider using http://webapps.calvin.edu/knightcite. Use it to save time, to make your writing error-free, and to avoid the maddening detail of citation formats.
Key fact: the "Works Cited" is a list of works that you have actually cited in the paper. If something appears in the works cited, it must also be cited in the text of the paper. The citations in the paper are called "in-text citations." There's a one-to-one correspondence between in-text citations and the items on the works cited page.
Formatting citations within the text of your paper is also difficult, but the Purdue OWL provides excellent examples at: https://owl.english.purdue.edu/owl/resource/747/02/ . This link leads to detailed information about MLA formats and about APA formats. Follow the link that meets the demands of the assignment you are completing.