on Just Publishing Advice:
Editing, copy editing and proofreading are separate processes in the preparation of a text in the publishing industry.
The three are used for a newspaper article, online content or a business document. But the processes are more commonly associated with preparing a manuscript for a book.
After the editing services are complete, a proofreader checks a text for spelling, grammar and typographical errors.
A professional proofreader usually uses a set of defined proofreading symbols from style guides to note errors in spelling, punctuation or omissions.