One way to achieve that is to use the gform_pre_render hook.
I once did something similiar to this on a real site.
add_action( 'gform_pre_render', 'show_content_before_fields' );
function show_content_before_fields( $form ) {
$custom_field = new GF_Field_HTML(); // temporary field object to hold our custom html
$custom_field->id = 0; // maybe unnecessary, can't remember if really needed
$custom_filed->visibility = 'visible'; // maybe unnecessary, can't remember if really needed
$custom_field->content .= '<h3>RMA' . $form['id'] . '</h3>'; // The actual custom html content
array_unshift( $form['fields'], $custom_field ); // Adds the custom field before the fields added in the form editor
return $form; // give the form back to Gravity Forms and let it continue it's doings
}
This code just adds arbitrary html code to the top of the fields list. The html doesn't (shouldn't) show up in the event entries / email notifications.
You should be able to toss this into your theme's functions.php or into a site-specific plugin.