Answer: The two most commonly used formats for bibliographies are in-text citations + a list of references at the end of the paper and endnotes or footnotes +/- a bibliography at the end of the paper 1. Scholars writing in the sciences and social sciences typically use in-text citations, while humanities scholars utilize endnotes/footnotes 1. The most common citation styles are APA (American Psychological Association), MLA (Modern Language Association), and Chicago 2 3.
I hope that helps!