In your academic work you are expected to provide references to the sources of information you used. These references are called citations. A list of citations is referred to as a bibliography. Providing citations serves several purposes:
You show where you got the ideas, text, or images for your paper. That is being academically honest!
Your bibliography shows how credible your work is, depending on the quality of sources you used.
Your readers can locate the sources you consulted and follow your research trail.
Not your very own thoughts or ideas? Give credit to the original author(s) by citing each of your sources of information!
Using someone's work and not giving credit is considered PLAGIARISM. Learn more about why you must avoid it!