Constant Content is an online platform I am a freelancer for. You have to take a basic writing test first. You can submit articles to their platform and their clients can buy them for full rights. You can't use the content anywhere else. I sold 80 articles there. You can set the price for the article. www.constant-content.com. You can write on a variety of topics. Content Writers is another platform I am a freelancer for. www.contentwriters.com. Hope that helps.

Sinem Gunel and Zulie Rane are two top writers that I follow on Medium. They write about copywriting and building your online brand as a freelancer. Hope that helps.