Go to Insert > Header or Footer.
Choose the header style you want to use.
Tip
Some built-in header and footer designs include page numbers.
You can add or change the text in the header or footer. To edit an existing header or footer, double-click it. For more information on things you can do with headers, go to Edit your existing headers and footers.
To eliminate a header, for example, deleting the header on a title page, select it and then check the Different First Page box.
Select Close Header and Footer or press Esc to exit.
To delete, select Insert > Header (or Footer) > Remove Header (or Remove Footer).
For more on headers and footers, see Headers and footers in Word.