What is the difference between proofreading and copy-writing?

If I were to proofread the very same question, I'd change copy-writing to copywriting. But as a copywriter, I may choose to rewrite it as 'Proofreading and copywriting--same or different'? 

As a copywriter, I create. As a proofreader, I ensure the creation is spotless. 

Proofreading and copywriting are different skills, and in some ways they are opposites. A copywriting is done by a highly specialist writer who works mainly in a technical, sales or marketing arena of a commercial sector while proofreading is done by a specialist in a language. Proofreading sometimes depends on the context, if the context is a literary work, the proofreader should be a highly specialise in a language; but if the context is a normal statement that shows some details about a certain work document, the proofreader could be anybody who has good knowledge in a language and can check and correct any possible mistakes in a document. 

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Proof reading an electronic copy of a publication to detect and correct production errors

of  a text or an art ,While,copy writing   is the act of writing text for the purpose of advertising or

other forms of marketing

Proofreading and copy-writing are skills that go together, but are far from the same.  Proofreading is a process of examinig text for mistakes, in essence editing a document.  Copy-writing is a creative process by which one develops text for the purposes of sales, promotion, or persuasion.  It will need to be proofread before it goes out to a customer to analyse and correct its grammar, wording, and clarity; that is where these two processes come together.

Proofreading is carefully reading a document and detecting errors (grammatical,spelling,or punctuation) that are to be corrected while Copy- writing is writing for the purpose of advertising or other forms of marketing.

However in both skills, the proofreader and the copy - writer must have certain qualities to perform well such as excellent knowledge of the written language, must have had formal training,must be able to meet deadlines, be patient, focused, meticulous, and have a good mastery of computer skills.