The purpose of an outline is to describe each chapter as its own entity.
It is also a great way to organize your thoughts and feelings, and any research you may have gathered for your book. Organizing your book this way helps you to work out plotting problems and develop character arcs.
Some literary agents and editors may request chapter-by-chapter outlines for novels, as well as a full synopsis. However, with nonfiction proposals, a chapter-by-chapter outline is essential.
Unicorn for Writers will review your existing outline and provide helpful comments, or create a chapter-by-chapter outline.