How Do Ebook Companies Really Help Authors

I’m exploring different publishing paths and keep hearing mixed opinions about ebook companies. Some authors say these companies simplify distribution and improve visibility, while others feel they limit control and profits. So my question ishow effective are ebook companies in supporting authors over the long term? Do they truly help with branding, sales, and reader reach, or are they mainly useful for beginners? I’d love to hear real experiences from writers who’ve worked with ebook companies and how it shaped their publishing success.