Editing and proofing are usually done via email with .doc or .docx files attached. Alternate methods may be arranged. There are different levels of editing.
Proofing: This is the final level of edit on a polished manuscript, usually in the publishing format, checking primarily for typos. If I did the comprehensive edit, you should have a fresh set of eyes to do the proofing. However, I do proofread for other authors.
Copy Editing: This is for manuscripts that have been refined based on feedback from a comprehensive editor and/or critique groups. These manuscripts are nearly ready for publication. Copy Editing includes details such as correction of spelling, grammar, and checking adherence to the appropriate style guide. Changes will be tracked so you can see each. If a continuity or similar problem is noticed, a comment will be provided, but that is not the focus of this kind of editing.
Comprehensive Editing: Also known as Substantive Editing, this looks at structure, content, and presentation. Have you achieved clarity and consistency? Does the story work? What might make it better? Is it suitable for the intended audience? You'll get specific comments and suggestions for revision. While Copy Editing is not the focus at this point, any noticed minor errors will be corrected as well.
As a Book Shepherd, I coach authors through manuscript preparation and the publication process. This includes any or all of the following:
Editing as needed.
Formatting interior for publication per industry standards (print and/or e-book formats).
Free worksheets offering guidance and instructions (with screenshots) to help you through each step in the self-publication process.
Additional help in following those instructions or other related work.
Cover design or assistance in designing your own if desired.
Image preparation and insertion. (Images need to be high resolution and different modes for print and e-books.)
Samples of books I've helped bring to publication are at the top of this page.
Co-authoring or ghostwriting
As a co-author or ghostwriter, I work with you to develop your fiction or non-fiction project into a manuscript.
Whatever services you require, I start by taking 20-30 minutes to look over the manuscript and do a sample of the work required. This is for FREE. It gives you a sample of what to expect and it gives me a chance to develop a reasonable estimate of the time that will be involved. Then I will offer you a contract with charges based on that estimate.
controlling your cost
The more polished your manuscript is before going to the editor, the less time they'll need to read and provide notes. A good comprehensive edit may still provide key suggestions.
I recommend finding a good critique group (libraries or bookstores can often help you with this). Good feedback will let you know where the manuscript is not working, where readers become confused or bored. The author always makes the final decision, but if you hear similar comments from multiple sources, your manuscript most often has a problem. Revise!
If you are doing non-fiction, make sure you've got all the information you need for citations. That includes author, title, publisher (and their location), publication date, page numbers used overall and specific pages for anything quoted. Make sure direct quotes are clearly shown as such and avoid carelessly rewording large tracks of text (aka plagiarizing).
If you are including foreign language and/or names that require spell-checking and/or accents, you might lower your cost by providing a list of those for the editor to use as reference. While they'll check your list, they won't have to create it.
More helpful hints for writers can be found at my blog.