This menu is dedicated to the configuration of headers and footers for all the pages of the document, including the title page.
There are two editing modes:
page header editing ;
footer editing.
This tab allows you to preview headers and footers along with the page content.
Separators are fillets whose purpose is to distinguish body content from header and footer content more immediately.
They are activated with checkboxes.
The header separator is placed at the bottom border of the header area.
The footer separator is placed on the bottom border of the footer zone.
This feature is used in connection with the configuration of the document in two-sided copy mode, available in the menu Page dimensions.
It allows you to show or hide the content of headers and/or footers on blank pages.
Headers and footers are created by dragging and dropping widgets.
The zone can accommodate widgets outside a grid, widgets grouped together in a grid, or a combination of both, as shown below:

Settings for widgets outside the grid include :
modification of height and width ;
positioning with XY coordinates.
Widgets grouped in a grid follow the grid settings.
Section Widgets describes widget types and how to edit them.