(mPDF >= 4.0)
Specify the behaviour defining the top-margin of the document. When $setAutoTopMargin is set to ‘stretch’ then $autoMarginPadding defines the minimum distance in mm that will be forced between the bottom of the header and the top of the main text.
pad - the value for margin-top is used to set a fixed distance in mm (padding) between the bottom of the header and top of the main text
stretch - margin-top sets a minimum distance in mm between the top of the page and the top of the main text, which expands if header is too large to fit.
FALSE - the defined value for margin-top is respected even if the header overlaps the main body of the document.