Notice the 'Title' style has the largest letters of all the styles. For instance, you might want to create a table of contents, and Word has styles that you use that will then tell the table of contents generator which headers are titles to new chapters and which ones are sub-chapters. There are a few styles that you'll use the most when you create long documents. Like other font changes, to change content to one of the styles in the list at the top of the document, highlight the text that you want to edit and then click the style. Even if you change a font style, color or size, you can still return to the default normal style by just clicking this selection. The default selection is the one on the far left named 'Normal.' The Normal paragraph format is what you'll use for most content. The styles section shows a preview of the letters, colors and font sizes that you'll see if you change a section of text to the style. Header styles are also found in the 'Home' tab, and you can find a long list shown in the center of the Word user interface. If you ever question where a style could be, the first place to check is the 'Home tab. Most of Word's most commonly used styles are contained in the 'Home' ribbon tab. Another advantage of using these preset styles is that they are used in some automatic tools such as creating a table of content. These presets make it much faster and easier to stylize your document without taking hours to create your own. It also provides preset formats for headers content and paragraphs.

Microsoft Word gives you more formatting options than just basic text changes.

Setting default font in word 2019