Before sending a proof to a Copy Editor, please ensure that you are familiar with Sending a Proof - The Basics
Send the Proof using the standard send proof workflow
When you see the below screen, add the collaborators to the proof.
Click the T icon next to the collaborator’s name that will require the copy editor role.
Tip! Don’t worry! If you need to add another copy editor at a later stage of the review cycle, you can add them on the Reviewers tab, on the Proof editor screen.
Continue with the GoProof wizard as normal, following any on-screen prompts.