Include headings that describe the topic or purpose of sections and components. The headings should represent an accurate outline of the content. Headings allow users to understand what information is contained in the document and how that information is organized.
Information that is conveyed through visual or auditory formatting, such as heading formatting, should be preserved when the presentation format changes (for instance, when content is read by a screen reader). When you apply heading styles through an application, it marks that text as being a heading in a way that can be perceived without visual cues.
Headings that both descriptive and correctly marked help everyone to understand and navigate documents. Descriptive headings are especially helpful for users with disabilities that make reading slow and for people with limited short-term memory. Descriptive headings also help people who use screen readers because headings are meaningful when read out of context, for example, in an automatically generated list of headings/table of contents, or when jumping from heading to heading within a page.
Visual cues such as larger fonts for headings allow sighted users to perceive the structure of a documents and find the information they need. When heading styles are used, this structure is also programmed into the document so that people using screen readers and other assistive technologies can perceive the same information.
For an example of how heading styles make formatting accessibility to people using screen readers, see this brief video demonstration.
Apply headings in order (starting with “Heading 1”) using the Styles drop-down in the toolbar, in between the Zoom and Font drop-downs :
Use “Heading 1” for the document title
Use “Heading 2” for section headings
Use “Heading 3” for subsections
Use “Normal text” for basic paragraph text
To save formatting to a style (to be applied to all text of that style):
Format text as desired and select text
Under the style, select “Update to Match”
To apply previously saved style formatting to text:
Select the desired text
Under the correct style, select “Apply”
For instructions with images, see this guide from WebAIM and select the version of Word that you are using.
Use the Styles drop-down to apply headings and the outline button to view the document outline. Don't use the Title or Subtitle styles. The document title should be labeled Heading 1.