Change “Invoice” to “Tax Invoice”

Of course, check out this documentation page: Change the document title

Thank you! That worked.

Hi,
I was also looking at altering “Invoice” into “Tax Invoice”.
Since we use the website to sell into Australia for local customers and also to export customers, I was wondering how to make Tax Invoice for just local customers.
The translation method only works for the WordPress site as a whole not by customer order country. If I make a translation file for US english then it works.

For Export invoice we are often asked to present as “Commercial Invoice”

Yes you can do that using the filter from the documentation linked above:
https://docs.wpovernight.com/woocommerce-pdf-invoices-packing-slips/change-the-document-title/#free-version

add_filter( "wpo_wcpdf_invoice_title", function( $title, $document = null ) {
	if ( !empty($document) && !empty($document->order) ) {
		$billing_country = $document->order->get_billing_country();
		if ($billing_country == 'AU') {
			$title = 'Tax Invoice';
		}
	}
	return $title;
}, 10, 2 );

Hope that helps!