What is copy editing?
Also known as line-by-line editing, copy editing makes sure you're saying what you think you're saying and in the way you want to say it.
Copy editors ask questions of the author to ensure that each word, sentence and paragraph is expressed as clearly as possible. Among other things, experienced copy editors ask:
Can this sentence be expressed more concisely?
Will the intended audience engage with these words?
Does the reader have all that they need?
Copy editing also checks grammar, spelling, consistency, puncutation and paragraphing, but is not replacement for a proofread.