In contrast with proofreading, which involves refining a text that has already been edited and structured, editing is more radical and incisive. It can involve anything from the conceptual organization of a text to editing for grammar and structure on the level of the sentence, the paragraph, or the entire text.
Editing also often entails creating or applying a style guide for overall consistency. Because editing digs deeper and requires more radical solutions to the problems of a text, it can also be more collaborative; the editor, for instance, might ask the client questions in order to establish a set of helpful parameters and clear guidelines before beginning to work in earnest.