Most authors who use a word processor do not use custom styles; instead, authors are in the habit of using the default Normal style and using the tab key and the formatting toolbar to customize headings and paragraphs. Unfortunately, this is a bad habit that will come to bite you later if you want to turn your manuscript into a print or ebook.

It is much better practice to control the formatting of your manuscript through styles. Styles are the foundation of best book practices, in particular ebooks: when your manuscript is converted to HTML, your styles are exported as the CSS (Cascading Style Sheet), which controls the look of your text in the ereader. Without styles, every paragraph in your manuscript will contain overrides, also known as bloated code. The use of styles creates much cleaner code and thus a much more stable ebook. The sooner you embrace styles, the sooner you will be on the road to creating a more professional manuscript and a more beautiful ebook. If you have already finished your manuscript and did not use styles, do not fret: you can create your styles now and then apply them to your text.

A style is akin to a recipe: it says this style equals whatever combination of font and paragraph formatting you input.

Styles can be quite specific to include any possible paragraph formatting from font type and size to paragraph alignment and indentation and Before/After values, and so on. The beauty of styles is that if you later decide to modify your document, you merely have to modify the relevant styles rather than go through your 300-page manuscript and fix each item one by one. For example, if you set your chapter heading to an 18-point font but later think this is too small, you can change the font size to, say, 24 points, and every chapter heading will automatically be changed to 24 points without affecting other text not based on that style, such as your body text.

Word has a number of default styles, the most obvious one being Normal, but also various heading styles, a hyperlink text style, a footnote style, and so on.

You can create your own styles to suit your document, or you can modify the default styles. It is essential, however, that you use Heading 1 for your chapter headings and modify to suit. It is also essential to use Heading 2 and so on as your subheadings, ascending one level at a time: Heading 1 is the top-level heading, usually displayed in the largest font; Heading 2 is the first-level subheading; Heading 3 is the second-level subheading, and so on. The reason for this is that most ebook devices are programmed to recognize the <h> (Heading) tags, so even poorly designed ebook devices or apps that otherwise ignore your code will still recognize your headings. It is the same if a user turns off publisher formatting. And ebook building programs such as Sigil need the <h> tags to auto-create a table of contents, and will automatically indent the subheadings in ascending value:

To modify a default style in Microsoft Word (other word processors will have a similar function), click on the Styles submenu on the toolbar to open the styles window (in Mac select Format > Styles). Before you continue, it can be very useful to click on the Options button in the lower right-hand corner and, in the window that opens, select “Recommended” under “Select styles to show:”. This reduces the lengthy “All styles” list down to a more manageable one.

In the list of styles that appears, pick the style you wish to modify; in this case we are modifying Heading 1:

Hover over the ¶ª symbol; it will change to an arrow. Click on the arrow and select “Modify” from the drop-down menu that appears. (Mac users: “Modify” is in the same dialogue box.)

In the dialogue box that opens, set your basic attributes: font family, size, style (regular, bold, italics, underlined), and color (always use Automatic for black); paragraph alignment; and line spacing (always use single for an ebook, but if you are at the draft stage of your manuscript you can use double for now and change it later to single before exporting to HTML). Click “OK” to save your changes.

Caution: if you intend to send your manuscript to a print book designer for layout or to an ebook designer for conversion, do not adjust the character spacing of your font (known as kerning). Print book designers will need to do that themselves, and fonts in ebooks should never be kerned. With regards to text effects, digital devices in general will recognize italics, bold, underline, superscript, subscript, and strike-through text effects. You cannot use double strike-through, shadow, outline, emboss, engrave, small caps, all caps, and hidden, and also horizontal scaling, raised and lowered text.

You can also choose to create your own styles.

To create a new style, click on the New Style icon in the Styles window (the first of the three icons in the lower-left corner). Input your new style’s attributes. Caution: all styles must be based on Normal. Give the style a name and click “OK.” Below is the style box and paragraph attributes for a style I call Main.

Repeat as necessary to create styles for all your different heading and paragraph formats.

To change a paragraph or heading’s style, simply place your cursor anywhere in the paragraph or heading and click on the style you wish to change to. This will apply the new style to the paragraph or heading.

Caution: Word can be unpredictable with character formatting when changing from one style to another, often erasing italics or bold text: if the character formatting is only part of the paragraph (the rest of the text being in regular font), the formatting tends to remain; but if the whole paragraph is in italics or bold, the formatting tends to be lost. Keep an eye out for any such changes so that you can fix them.

Character Styles
Just as you can create custom heading and paragraph styles, you can also create custom character styles. For example, if you want the first letter of the first paragraph in each chapter to be a larger size, you should not use a paragraph override; you should instead create a character style. (Note that this is not to be confused with creating a drop cap; drop caps should not be used in your manuscript as they must be created separately in a print or ebook.)

Click on the New Style icon in the Styles window. In the window that opens, name your character style, and in the drop-down Style type menu choose “Character”. Make the necessary changes.

One caveat: if at this stage you want to add a bit of color to your manuscript, you can change the font color via character styles. Be warned, however, that colored text will merely display as a shade of gray on grayscale devices, and may disable the user’s ability to change their screen color in devices with this option. Use only if really necessary.

Another use for character styles is with regard to underlined text. In Word, when you highlight text and click on the underline icon, Word brackets the text in the <u> tag that you will see when you save to HTML. If you instead create and assign a character style called Underline to the same text, in the HTML you will see <span class=Underline>. The <u> tag is still accepted by Kindle but has been deprecated (made obsolete) in ePub code; ebooks with the <u> tag will fail validation, but those with a span class will pass validation. If you intend to build both a Kindle book and an ePub using the same Word document as your source, getting into the habit of creating a character style called Underline will save you the bother of having to fix this issue later in your HTML.

You can also create a character style for text in a different language, so as to tell ereader devices to open the appropriate dictionary when checking a word in this foreign language. Currently, most ereaders will only open the dictionary of the language specified in the header code, but some devices will allow users to download multiple dictionaries and select which dictionary they want to look a word up in (though this means the definition will also be in that foreign language). In future we can hope for translation dictionaries, and if you have the code in your book the user can take advantage of that if and when it happens.

A final word of caution: do not use Word’s built-in styles to create tables. These need to be built from scratch by your print book and/or ebook designer.