It is an organized, annotated ('with notes') list of resources. It includes all of the books, articles, reports, and other types of resources that you read for your project.
Here is a great handout from the UNC writing center on writing an Annotated Bibliography:
The abstract of an article or book is just a summary of the contents. For an annotated bibliography, you want to describe the main points and evaluate the content, structure, or conclusions. You may also consider how useful or relevant it is to your research topic.
Will you remember every detail from the articles, reports, and books that you read? If so, that's great for you! But for the rest of us, it's handy to have a bit of a reminder while we're writing the paper
Key points, conclusions, or recommendations
Surprising or interesting findings
May include questions related to:
Author bias, Scope, Structure, Conclusions, Methodology, Relevance, Timeliness
How does this inform my project?
Is it useful? If so, what section of my project is it most applicable?
Begin the annotation with an introductory sentence explaining what the resource is; do not copy and paste the abstract. Maybe you can include something about the author’s research methods. Annotations can be 1-3 paragraphs, but the most important thing to keep in mind is that you want this to be useful for you as you continue your research.
Example is taken from Roger Williams University using APA format.