A citation or source citation is a reference to a published work (for example, a book, article, image, etc.,) that is used when creating a written work. It shows readers where specific pieces of information came from and where readers can locate it for themselves.
It acknowledges or gives credit to the author who actually created the content being used in a paper. The opposite of a citation is plagiarism, or not giving credit to others for their ideas, concepts, or images. Plagiarism, especially in Academia, is considered taking the work of others and presenting it as one's own. The penalties for plagiarism can be severe. Source citations also give a work credibility. In other words, it shows the information is simply not made up.