You’ve updated an old document with new information and now you want to update a header or footer.
Double-click the header or footer area (near the top or bottom of the page) to open the Header & Footer Tools. Select the text you want to change and type your new header or footer. Double-click the body of the document to close the Header & Footer Tools.
To also change the design of the header or footer
You can change the look of a header or footer with dozens of built-in designs in the Header & Footer Tools. In the Insert tab, click the arrow below Header or Footer and then select the one that you want. This overwrites your current header or footer and you’ll have to type the information in again.
You can also add graphics to your header or footer. When you are finished with headers and footers, close the header and footer tools by double-clicking the body of the document.
Tip Adding page numbers? Read Insert page numbers or add different page numbers in different sections.