A style is a collection of character and paragraph formats you can apply to selected text. Each Word document includes several default styles, and you can modify those and add your own. Each style has a name. Word comes with several styles, and you can also create your own.
Click the drop-down arrow on the Style box. (You might have to click the More Buttons button at the right of the toolbar to see the Style box drop-down list arrow.) You will see the names of the document's styles. After you select a style, Word applies it to the current paragraph and subsequent paragraphs that you type.
If you want to change a style's formatting or create a new style, select Format, Styles and Formatting to show the Styles and Formatting task pane. (You can also click the Styles and Formatting button to display the task pane.) To modify the current style, click on a style and open the style's drop-down list to choose Modify. If you want to create a new style, click the New Style button.
Suppose that you routinely write résumés for other people. You might develop three separate sets of character and paragraph formats that work well, respectively, for the title of a résumé and an applicant's personal information and work history. Instead of defining each of these formats every time you create a résumé, format a paragraph with each style and store the styles under their own names (such as Résumé Title, Résumé Personal, and Résumé Work). The next time you write a résumé, you need only to click the Style box's drop-down list arrow and select Résumé Title from the style list. When you then type the title, the title looks the way you want it to look without your having to designate any character or paragraph format.