Copywriting is the use of words and ideas to promote a person, business, opinion or idea. wikipedia.org

Copy editing (also written as copy-editing or copyediting, and sometimes abbreviated to ce) is the work that an editor does to improve the formatting, style, and accuracy of text. Unlike general editing, copy editing might not involve changing the substance of the text. wikipedia.org

Proofreading (also proof-reading) is the reading of a galley proof or computer monitor to detect and correct production-errors of text or art. Proofreaders are expected to be consistently accurate by default because they occupy the last stage of typographic production before publication. wikipedia.org

A ghostwriter is a professional writer who is paid to write books, articles, stories, reports, or other texts that are officially credited to another person. wikipedia.org

Technical editing involves reviewing text written on a technical topic, and identifying usage errors and ensuring adherence to a style guide.

The Chicago Manual of Style is a style guide for American English published since 1906 by the University of Chicago Press. Its 16 editions have prescribed writing and citation styles widely used in publishing. wikipedia.org