Although you might hear the terms used interchangeably, proofreading and copyediting (or line editing) refer to different services. Most professional texts will go through both services before publication.
A copyeditor will help to improve your writing by aiming to enhance the clarity, flow and tone. While a copyeditor will also catch typos and grammatical mistakes, that’s not all they’re looking for and they’ll often suggest larger changes to improve your text.
A proofreader offers a final chance to catch spelling errors, grammatical mistakes and layout issues before you make your work public. Since proofreading occurs right at the end of the publication process – after a copyedit – a good proofreader will avoid making substantial changes to the text, which run the risk of introducing new errors. Instead, a proofreader will only change that which needs changing.
In short, if your writing hasn’t been professionally copyedited yet, it probably isn’t ready for proofreading. Copyediting is a service I aim to provide in the future, but until then you can find many professional copyeditors in the CIEP directory.