A bibliography is a list of the sources you used for an essay or research project. The bibliography is also known as the "works cited" or reference list.
An annotation is a summary or evaluation of the source and how you used it in your assignment.
An annotated bibliography is a list of citations where each citation is followed by a brief paragraph (annotation) that analyzes the cited source. The purpose of the annotation will vary depending on what your instructor is requiring for the assignment. Typically, the annotation serves to inform the reader of the relevance, accuracy, and quality of the source.
The citation comes first. For this part, you are simply listing the information about the source in the format that is required by your instructor. In most cases, you will use either APA or MLA format.
The second part is the annotation. The annotation is basically "notes" that you are writing about the source. The length of the annotation will vary depending on the instruction given in your assignment.
In order to create an annotation, you might start by answering the following questions about the source (article, book, website, etc.). However, make sure that you refer to your assignment and follow the instructions provided by your teacher.