Proofreading of texts
used if you need to edit or add to a text you have created, such as business correspondence, emails
Proofreading by a native speaker
used when it is not just grammar that counts, but also the stylistic accuracy of a translation (phrasing, local idiosyncrasies). The final text will be fully comprehensible for native speakers in the country in question. Essential for localisation.
proofreading the pre-print version of a text before publication to check typographical layout and correct any typographical errors. Used for texts that are to be published.