Search engine optimization (SEO) has changed a lot over the last two decades. Thankfully, the games people used to play to try to push their web content to the top of Google search results are largely a thing of the past. Site optimization is important, but that's behind-the-scenes coding that online content writers don't need to worry about.
There isn't a lot that writers need to know about on-page SEO, and a lot of what they need to understand is just common sense: