Yes, of course, you can sell your book to a publisher after self-published but it only requires one thing which is a large number of copies sold. If the writer shows a big number of sold copies to the publisher like 10k or 50k then the publisher will probably buy it. Otherwise, there is a very low chance that any publisher will put his hand on something that hasn’t been sold. That is why the writer needs to follow the guidelines carefully before self-publishing a book. Because many new writers make the mistake of publishing their books on their own. And when the book doesn’t sell then they run towards the publishers. So, that is why you can always ask for assistance while doing anything like write an essay for me or publishing a book.