This is usually what happens when copyediting a document...
You email me the document(s) and brief; we agree a deadline.
In Word, I track all the changes so that you can go through accepting or rejecting them. (I can also mark up amends on a PDF.) Where appropriate, I’ll also supply you with a style sheet (a summary of the ‘recipe’ followed for consistency of punctuation, spelling, numbers, etc).
You review my edits and let me know if you have any questions.
I’m happy to look at something again if it needs further work, although this happens rarely: I’m often told that even if I occasionally misinterpret a sentence, this is equally helpful because it shows the writer how they need to explain things differently.
I have a borderless account with TransferWise, which means that I can accept payment in most currencies without the payer incurring bank charges. I usually invoice at the end of each month and am paid within 30 days of the invoice.