6. Creating and Applying Styles and Themes
Styles are named formatting definitions that you can apply to text to ensure consistency within a document. For example, you could apply the Heading 1 style to all headings in the document, and all the headings would be formatted in the same way.
Styles also make it easier to make global changes to the formatting in a document; when you modify the style, all text based on that style is automatically updated. Suppose you decide you want all the headings to be underlined—just turn on underlining for the Heading 1 style and you’re done.
Word uses styles not only to standardize document formatting, but to control the organization in outlines, tables of contents, and master documents. ...