Proofreading or copyediting?
It's common for people to use the terms copyediting and proofreading interchangeably, but each refers to a distinct process at a different stage of production, and each addresses a different category of textual issues.
Copyediting occurs before typesetting (the latter being the process of page layout for print) and, according to the Chicago Manual of Style, "consists of both mechanical editing and, where needed, substantive editing." As the final stage of editing before publication, the copyediting process "prepares an otherwise final manuscript for publication." This requires "attention to every word and mark of punctuation in a manuscript, a thorough knowledge of the style to be followed, and the ability to make quick, logical, and defensible decisions."
Proofreading, meanwhile, "entails reviewing a work for any remaining errors after the manuscript has been typeset for publication in print or converted for publication as an ebook or online—but before it has been published."
Copyediting reviews texts for errors that pertain to the usage of grammar, spelling, and punctuation, while proofreading occurs later and reviews texts for mechanical errors that either remain or were introduced during typesetting.