I decided to post this information because of my experiences involving editing and writing novels. When hired exclusively for editing, I explain that editing is not the same as copywriting.
A copywriter may be hired to improve the content or actually create content for an article, website, or project. The copywriter rarely gets as much credit for creative processes as the editor on a project. The copywriter may also be responsible for correction of the grammar, punctuation, and spelling errors in the work.
Editing, especially extensive editing, requires a knowledge of appropriate structure, syntax, and style of writing appropriate for the audience being addressed by the author’s work. The editor makes suggestions of clarification concerning words, statements, or verb agreements and consistency of style to the author. Basic corrections of grammar and punctuation are identified. The author then makes changes as suggested and returns the work to the editor for another review. This process may take several revisions in order to produce a professional finished literary work. In some cases, an editor may have discussed with the author their willingness to have punctuation, grammar, and word choice changes done by the editor during the first reading. If this is the case, make sure as the editor or the author that those terms are clear.
In the end, it is the author’s words that should stand out in the finished product. It should not be modified to fit the literal voice of the editor. The author should be willing to decline any changes made by the editor in order to preserve the intended message of the work. Just know that at the larger publishing houses, the author may lose the battle of revision to the editor if they wish to have their books published by that house. Read your contracts carefully and make all terms of any job clear before you proceed as the author or the editor.