array key: header

The header array item is a HTML string that is displayed between the menu title and the input form. It is displayed within the form so form variables can be embedded, any HTML content will be displayed. HTML is recommended and conditional logic may be used.

$id = isset($_GET['id']) ? $_GET['id'] : 0;
$input_form_definitions['header'] = $id > 0 ? '<p>Edit car below with this form.</p>' : '<p>Input new car with this form.</p>';