openstamanager/templates/base/settings.php

<?php

$settings = [
    'orientation' => 'P',
    'format' => 'A4',
    'font-size' => 10,
    'margins' => [
        'top' => 10,
        'bottom' => 10,
        'left' => 12,
        'right' => 12,
    ],
    'header-font-size' => 10,
];

return $settings;