Editing and proofreading are two different stages of document preparation. Every author invariably hires a professional proofreading and editing service once he/she has finished writing the first draft of the document.
The abundance of online proofreading and editing services makes it easy for authors for hire a second pair of eyes. However, to help you express your thoughts clearly and coherently, it is key that the editor and proofreader are familiar with not just your area of work but also the subject-specific conventions.
By definition, proofreading is a surface-level check. It is the final check performed on a document. A proofreader will look for misspellings, incorrect/missed punctuation, inconsistencies (textual and numerical), etc.
Editing, on the other hand, corrects issues at the core of writing like sentence construction and language clarity. A thorough editing will help improve the readability, clarity, and tone of the text. An editor will scrutinize and polish your writing for a smooth narration.