At first, I didn't want to add Fiverr to this list because there are a LOT of editors on Fiverr that aren't exactly a good investment. But, that doesn't mean there aren't amazing opportunities out there. Editors like Kerrie McLoughlin, have done an amazing job with their Editor Fiver gigs. However, if you do decide to go through Fiverr, then ABSOLUTELY use my test to ensure you aren't hiring someone who isn't qualified.
I'd suggest working through each change so you can learn for next time, rather than just clicking Accept All on the Track Changes version. This will take time, but it's well worth it. I usually accept 80-90% of my editor's changes and the manuscript is improved considerably by the experience. After the line edits are updated, I send the manuscript to a proofreader for the final check before publication.
Software and Systems – Some of us writers like using certain types of writing tools or software. I personally love to write my books using Scrivener, and will then switch to Google docs for better tracking systems. However, I've run into editors who only use Word document. That's no bueno for me. So, make sure they are good with whatever writing programs you want to use.