Headings (e.g., H1, heading 1) let you organize your content into an outline of topics and regions. This nested document structure makes it easier to quickly scan and navigate your document. Some formats use headings to create bookmarks, tables of contents, and other navigational aids.

Page title and language, appropriate sectioning, semantic elements, and metainformation are other elements that can help people better understand how to read and navigate your document. 

Tips for providing good structure

• If your document supports metadata, provide title, language, summary and other descriptive information 
• Use a first-level heading to provide a meaningful visual title for each document; this should match the title in your metadata, if any
• Separate your document into sections, regions, or landmarks where appropriate
• Use level 2 headings to introduce new topics or sections in your document
• Do not skip heading levels
• Use headings to provide a table of contents, bookmarks, sitemap, or other navigational supports for your end user
• Do not use headings for blocks of body text or for stylistic purposes
• Do not use tabs to simulate columns, tables, lists, or other structures