1 Open a new document and select. 2  Select a new font and size in the Font dialog box, and then click Default. 3  Word will ask you if you want these changes to apply to all new documents using the Normal template (normal.dot). 4  Click Yes to make the changes permanent.his document details how to change the default font, font size, and page margins in Word. 1  Word 2003 and Word XP. 2  Open a new document, click on the Home tab, click on the Font dialog box button as shown in the screenshot below, and select the Font tab.