The styles feature in Word allows you to quickly format a document with a consistent and professional look. Word has a selection of preset styles to choose from. If you want more freedom to design the look of your document, you can store the formatting instructions for your headings, subheadings, font style, text spacing, and more in the form of a style, and then use that style to easily format and edit your entire document. You can also save the paragraph and character styles you create, and use them in some of your other documents.

Heading styles are especially important to maintaining document organization and accessibility for people who use assistive technologies such as screen readers and braille devices. Formatting the sections and subsections of your document with consistent Heading styles (instead of adding bolding or changing font size without using a style) helps people without eyesight to understand the structure of a document and to be able to navigate between subsections of the document. If you have more than one level of organization in your document (for example main sections that are subdivided), you should maintain the hierarchy of heading styles, using Heading 1 for your main sections and Heading 2 for the names of subsections, and Heading 3 for smaller divisions. It is possible to maintain accessibility while customizing the look of your document further by modifying the qualities (such as fonts, or text size and color) that styles have without changing the names of the styles. For more detailed information on creating accessible documents in Microsoft Word, please read the guidelines published here. 

In addition to accessibility concerns, heading styles are also crucial when creating automatic tables of contents (you can read more about tables of contents here) and when exporting to pdf to preserve document organization and derive 'bookmarks' of different sections and subsections in pdf's navigation function.

This section will show you how to apply a style, create a new style, and modify and delete styles.

Applying a Style

To apply a style to a paragraph or portion of text:

1. StepsActions
1. Select the text you want the style to be applied to. To format your title, you can use the "Title" style, to format your headings, you can use the various "heading" styles, and so forth.
2. Click the Home tab.
3. Select a style from the thumbnail options in the Styles group. To see a preview of what a style looks like, hold the mouse over the thumbnail option. To see more styles, click the arrow on the right of the Styles group.

Adding a New Style

You may want to create your own style, and add it to the Styles group on the Home tab so that you can access it easily and quickly. To add a new style to the Styles group:

1. StepsActions
1. Create the style by applying your preferred text attributes, for example font face, size, and color, to a portion of text.
2. Select the newly created style.
3. Click the Home tab.
4. Click the arrow  on the bottom-right of the Styles group. The Styles dialog box will open.
5. Click the New Style button  on the bottom-left of the dialog box.
6. Type a name for your style in the Name field.
7. Click OK.

Modifying and Renaming a Style

To modify a style:

1. StepsActions
1. Click the Home tab.
2. In the Styles group, right-click the thumbnail of the style you want to modify if you are using a PC, or control-click the thumbnail of the style you want to modify if you are using a Mac. A shortcut menu will open.
3. Click Modify. The Modify Style dialog box will open. From here, you can change the font style, spacing, headings, and more.
4. 
5. When you have selected your modifications, click OK.

To rename a style:

1. StepsActions
1. Click the Home tab.
2. In the Styles group, right-click the thumbnail of the style you want to rename if you are using a PC, or control-click the thumbnail of the style you want to rename if you are using a Mac. A shortcut menu will open.
3. Click Rename. A dialog box will open.
4. Enter a new name for the style.
5. Click OK.

Deleting a Style

Preset styles created by Word cannot be deleted, but to delete a style you have made:

1. StepsActions
1. Click the Home tab.
2. Click the arrow in the bottom-right of the Styles group. The Styles dialog box will open.
3. Click the Manage Styles button . A dialog box will open.
4. Select the style you want to delete from the list.
5. Click Delete.
6. Click Yes.
7. Click OK.