Alter PDF file name - WebToffee PDF invoice plugin for WooCommerce

functions.php

<?php

add_filter( 'wf_pklist_alter_pdf_file_name ', 'wt_pklist_change_pdf_name', 10, 3 );

function wt_pklist_change_pdf_name( $name, $template_type, $order_ids ) {
	if ( $template_type == 'invoice' ) {
		if ( count( $order_ids ) > 1 ) {
			$name = 'facture_bulk_' . implode( '-', $order_ids );
		} else {
			$name = 'facture_' . $order_ids[ 0 ];
		}
	}
	if ( $template_type == 'proformainvoice' ) {
		if ( count( $order_ids ) > 1 ) {
			$name = 'factureproforma_bulk_' . implode( '-', $order_ids );
		} else {
			$name = 'factureproforma_' . $order_ids[ 0 ];
		}
	}
	return $name;
}