Citations are description of a source. Here is an example of a citation on an APA reference page:

Delhy, R., Dor, A., & Pittman, P. (2021). The Impact of Nursing Staff on Satisfaction Scores for U.S. Hospitals: A Production Function Approach. Medical Care Research & Review, 78(6), 672–683. https://doi-org/10.1177/1077558720950572

It includes information so that others can locate the source you used. The above citation has the authors names, year of publication, title of the article, journal, issue and page numbers as well as a permanent URL for the article. You cite sources to credit other authors, who's ideas you are including in your own work. It also uses a "hanging ident", the second line is indented, this makes it easier to read a list of multiple references. 

There are several formal "styles" of citation that provide rules for how you format a citation for consistency, typical style used at Blackhawk is APA. Ask your instructor for their citation instructions.