As you probably know, a header is a text box that appears on every page of your document and a footer is a similar text box that appears at the bottom of every page. You can fill these boxes with the text of your choice. Headers and footers are very useful if you want to number the pages of your document, put your name of each page or put a date on each page.
In order to create a header or footer in a Word document, select View from the top menu. Look there for Header and Footer. This should bring the Header and Footer toolbar. To have your computer automatically number your pages, click Insert Page Number. To fill the header and footer box, go to this box and put your text. After you have done what you wanted, close the header and footer menu.