Use this code example to change the array separator of array value to '|'.

add_filter('frm_pdfs_show_args', 'change_array_separator');
function change_array_separator( $show_args ) {
	$show_args['array_separator'] = '|';
	return $show_args;
}

Use this code example to display the filename of an uploaded WordPress file in the exported PDF.

add_filter('frm_pdfs_show_args', 'show_filename_upload');
function show_filename_upload( $show_args ) {
	$show_args['show_filename'] = true;
	return $show_args;
}

Use this code example to show empty or blank fields in the exported PDF.

add_filter('frm_pdfs_show_args', 'show_blank_fields');
function show_blank_fields( $show_args ) {
	$show_args['include_blank'] = true;
	return $show_args;
}