Editors do acquisitions, manuscript and project development, research, structural editing, stylistic editing, rewriting, fact checking, copy editing, picture research, proofreading, indexing, layout and production editing. Professional Editorial Standards describes a number of these key roles.
what does an editor do?
In charge of refining and checking the product, they make sure it performs as well as it can - technically, artistically and for its target audience. A newspaper editor would make sure that the newspaper content is accurate, that it looks professional and is in line with previous editions.