Self publishing is the way to go most of the time! If you go through a publisher, they are going to take such a large cut of the profit, but they aren't going to do much for the cut that they take. Unless of course you can get a HUGE publisher interested in your work, but that's extremely difficult, obviously. You'd spend so much time writing query letters, figuring out how to write them, who to contact, etc. You would think that publishers would help marketing at least some, but the truth is, most don't!
My husband has written two books and self published through Amazon's company Create Space. We did a ton of research and now we even have a business helping people write their books. He does the content portion, knowing how to actually write the thing, and I do the editing portion. In regards to having something edited, you can definitely find an independent editor that will charge a reasonable rate. Often times, they will also help you format the document so it can be correctly uploaded to whatever platform you use to publish it. (Most books start out as a word document, and there's a process to make it into an actual book!
If you go through a traditional publisher, they usually have a minimum amount you can order. With Create Space, you can order one book if you want. It's a print on demand service, which means the books are made when someone orders them. You can order in bulk and sell them in person, or direct people the Amazon page to order themselves.
There is a lot more that I can share, but this is a good place to start! I put this here instead of messaging you because others may have the same question. Feel free to send me a message