How do I append a div container to a specific area of a webpage?

I am asking this question because all of the other answers that I found are dealing with JQuery. I am not using JQuery, just pure JS.

Currently I create a div and add content into the div using Create Element and innerHTML. I then use appendChild on the body of the document to add the HTML to the document. The issue is that the injected HTML is at the very bottom of the body but I want it at the top.

How can I do this?