You can automatically format a document either as you type or after you've written it. In both cases, you can control which automatic changes Word makes. You can also turn off automatic formatting.
Word analyzes each paragraph to see how it's used in the document
Formatting as you typeWhen you set options on the AutoFormat As You Type tab (Tools menu, AutoCorrect Options command), Word can automatically format text as you're typing your document. For example, if you type a number followed by a period or hyphen, followed by a space or tab, followed by text, Word makes the text a numbered list.
When Word applies automatic formatting, you can use the AutoCorrect Options button 
to undo the action or change AutoFormat settings. Depending on the situation, the entire button may appear or the button may first appear as a small, blue box that changes to a button icon when you point to it.
When you use the AutoFormat dialog box (Format menu, AutoFormat command), Word can format text in one pass, enabling you to review all the changes Word makes and accept or reject each one.
Notes
- In addition to using AutoFormat, you can use the Styles and Formatting task pane to help format your document quickly.
- The AutoCorrect Options button is not available when you run AutoFormat after you type. You can, however, review AutoFormat results and determine whether or not to accept a change.