As long as there is still the written word, there will always be editors. Freelance editing and proofreading not only pays a decent hourly wage, it also gives you the chance to read about potentially interesting topics too. What's more, pursuing freelance writing & editing as a business idea can afford you a lifestyle that lets you travel the world as a digital nomad. You can find lots of job postings from companies and individuals in need of writing, proofreading, and editing services on Upwork, which makes this a high-demand opportunity to make money online.
Now, this isn't about some get-rich-quick method here. If you want to get rich quick, forget about trying to do it on the internet. Sure, Facebook ads are all the craze, but without a serious understanding of the mechanics behind sales funnels and conversion optimizations, which only comes after years and years of in-the-trenches work in the internet marketing field, you're largely wasting your time trying to "get rich quick."