How to reduce the size of the header / footer in microsoft word?

I have a problem using Microsoft Word.

I can increase the size of the header by placing some text or images inside, but then it's impossible to reduce it later.

I have tried reducing the margins but it only moves the text and don't reduce the size of the header.

Do someone know how to do it ?

Thanks,

SLP

Display the Page Setup dialog box. For example, you can double-click the vertical ruler. Or you can click the dialog launcher (the little arrow on the bottom righ) of the Page Setup group on the Page Layout tab.

On the Layout tab, make sure that "Vertical alignment" is set to "Top." Also, look a the margins specified on the Margins tab.