The 6 levels of editing are: developmental editing, substantive editing, copyediting, line editing, proofreading and final review.
Developmental editing is the first and most in-depth stage of editing. This type of editing focuses on the larger picture aspects of a manuscript, like overall structure and organization, flow, readability, and content. Developmental editors help authors determine the best focus, clarity, approach, and marketability of their material.
Substantive editing is the next level of editing that follows developmental editing. It requires an in-depth understanding of the content to identify gaps and suggest improvements in the tone, organization, and structure. Substantive editors focus on the issues of accuracy, clarity, and readability.
Copyediting is the next level of editing, focusing mainly on the stylistic elements. Copyeditors correct the language and make sure the text is clear and consistent. This involves checking for grammar, spelling, consistency, voice, and vocabulary.
Line editing is the next level of editing and involves making revisions to the text to ensure clarity and smooth transitions from one idea to another. Line editors also look for repetition, awkward phrasing, wordiness, and overuse of jargon.
Proofreading is the final stage of editing and it's about catching any typos or missing punctuation that may have gone unnoticed in earlier stages of editing. This is the last chance to make sure all the spelling, grammar, punctuation, and formatting are perfect.
Final review is the final step of editing, where a second editor reviews the work. This helps to ensure that all previous levels of editing were done properly, and nothing was missed. This level of editing also helps to identify any conflicting or out-of-sync content and resolve any issues with the formatting and layout.