Table of contents
Headers aren't just for boosting readability, they also automatically generate an outline of the content contained within a document.
Add a table of contents block in your docs
You may type
/outline or /toc within a doc to place a table of contents in the doc's content.
Once you have your headers in place, you can bring order to even your longest docs. 
See the doc outline outside of its content
You can see your doc's outline via the "Show table of contents" link that is nested in the 3 dot menu in the top right of a doc:
Any text to which you've applied the H1, H2, or H3 headers will be listed (and linked) in the table of contents for your doc.
