Before a writer's material is sent to press copy editors check it for errors in grammar and punctuation and they make necessary corrections so that the piece follows the style that is supposed to be used for a particular publication. Thus copy editors must be familiar with a publishing company's rules on grammar punctuation and reference citation. In addition copy editors often check the facts in a written piece to make sure they are accurate and they look out for anything that might be considered defamatory in nature.
The website Theslot.com states that depending upon the publication copy editors may be allowed to make major changes in how a piece is written. For example they may insert improved paragraph transitions or delete repetitive or unnecessary phrases. As such this website refers to them as a "last line of defense against bad writing." For extensive changes however copy editors usually check with an assigning editor.
Copy editors usually have at least a bachelor's degree typically with a major in English or journalism. They can work for newspapers magazines or other publishers or production houses but some of them are freelance and work for many different organizations. Work for online publishers is increasing although jobs are competitive.
The website Ehow.com reports that annual salaries for copy editors range from approximately $31500 to $49300. Those who work for companies also get benefits while freelance copy editors usually do not.