Use built-in styles to create Headings
1. Select the text you wish to use as a heading.
2. On the Format Text tab, in the Styles group, select a heading style, for example, Heading 1 or Heading 2.
You can also use key commands to create the different headers i.e. ‘Alt + Control + 1’ creates a heading level 1. ‘Alt + Control + 2’ creates a heading level 2 and so forth.
If you have different heading levels (such as Major, Section, Subsection, etc.) that look different, you must use a different Style for each type of heading. You can modify Styles so that you can create the look and feel you want in your message.
Use headings in logical Order
A common sense approach to headings and sub-headings makes a document much easier to follow. Headings serve as navigational aids for readers, and help writers organize thoughts more logically than they might otherwise. For example, organize headings in the prescribed logical order. Use Heading 1, Heading 2, and then Heading 3, rather than Heading 3, Heading 1, and then Heading 2.
In addition, organize the information in your documents into small chunks. Ideally, each heading would include only a few paragraphs.