Documenting your sources gives credit to authors whose thoughts and ideas you have incorporated into your work. Proper citation helps you as a writer by strengthening your position and showing the depth of your research.
It is vitally important to be respectful of the sources you are relying on for your scholarly work. The University Library's Academic Honesty web page is a good source for discussions of what academic integrity means, what plagiarism and other forms of academic dishonesty mean, and what the sanctions for academic dishonesty are.
Because of the wide variety of sources used in public policy, you will be exposed to a spectrum of academic citation styles. You will have to ask your professors which citation style they prefer, and if a resource uses a different style, you will have to convert your citation to that resource to match your professor's preference. Fortunately, there are many programs which help you convert, although they are not error-free.
Different academic disciplines follow different formats for presenting citations, so check with your instructor to make sure you are using the appropriate citation style. Here are some commonly-used citation styles: