Copy editing is the most technical of the editing processes. It focuses on making sure that the document is consistent, correct, and adheres to the specified style guidelines. I will: 

• Correct grammatical and usage (word choice) errors
• Ensure that the mechanics of style (such as spelling, punctuation, capitalization, hyphenation, and the use of numbers and symbols) are applied in accordance with
  the specified editorial style, and that they are applied consistently throughout the document
• Query possible errors in accuracy and internal inconsistencies in facts
• Flag potential copyright issues

You will receive a style sheet that lists anything for which I made an editorial decision (such as whether or not to hyphenate a particular word, which spelling variant to use, and whether to spell out numbers or use numerals). A style sheet will help you and and any other people who work on the manuscript maintain consistency.