Good question.
For starters, let's make sure we understand the definition of a bibliography. A BIBLIOGRAPHY is a listing of citations -- usually including the author, title, publication information, etc. -- of the sources you have used or plan to use for your research topic (Ellison, 2010, p. 55). Bibliographies help the readers of your research find out where you obtained your information. Instructors and others use them to assess the validity of your research findings and aid future researchers in locating sources on similar research topics. Bibliographies are also sometimes referred to as Works Cited pages or References. Depending on the style you are required to use, citation formats will vary. You should consult your professor, the appropriate style guide (MLA, APA, Turabian, etc.), or the library's Citation Help guide to learn more about formatting bibliographies.
An ANNOTATED BIBLIOGRAPHY goes one step further. An annotated bibliography provides a short paragraph of description/criticism/evaluation of each of your sources. Annotated bibs can help you remember specific information contained in your source and often act as a springboard to further research because you are able to see what has already been written about your topic (Ellison, 2010, p. 56).
Ellison, C. (2010). McGraw-Hill’s concise guide to writing research papers. New York: McGraw-Hill.
Citations are listed alphabetically and are followed by a short paragraph providing information about the work. Citation formatting information can be found within the style guide that you are required to use. Check the Citation Help LibGuide or consult your style manual.
For additional examples of annotated bibliographies, click on the links found in the "Annotated Bibliographies Toolbox" at the top of this guide.
When in doubt, your professor is your best resource. He/She created the assignment and has a specific idea of what your completed assignment should look like. Don't be afraid to ask questions. We're all here to help you learn.