Copyeditors basically read the content completely and ensure that they are free of errors. They also make sure the writing is easy to read and fits the publication's editorial style. Some copy editors are employed at magazines, newspapers, and online publications, while other copy editors work on a freelance basis.
Copy editors begin the editing process and attend to both style and language editing. In terms of style, they ensure that the design/layout is followed and that all scientific conventions are handled correctly. They also ensure that references are fixed consistently. In terms of language editing, they read the text and correct gross errors in spelling, punctuation, word choice, grammar, and the like. They also add queries to the author as appropriate.
Each publisher has one’s own style guide, which outlines their style preferences and word choice. Copy editors ensure that articles comply with the publisher’s style guide. They work closely with writers, suggesting changes to enhance articles' readability, conciseness, and style.
The job demands an eye for detail, patient analysis and reading of the text, good English language skills, and ability to spot mistakes and correct them as appropriate.