Set the margin top/bottom in the properties of the Template itself. This margin applies to everything except the header and footer. If you want to give the header/footer margin you can set this in the properties of the header/footer itself.
For example if you set the Template margin-top to ‘2’ and the header margin to ‘0’ the header stays at te top of the page, but the other content wil be placed lower on the page
Adjust the header margin in your template.