Add sections / fields to Invoicing with InvoiceXpress for WooCommerce - Pro

invoicexpress_woocommerce_settings_tabs.php

<?php
add_filter( 'invoicexpress_woocommerce_settings_tabs', 'my_invoicexpress_woocommerce_settings_tabs' );
function my_invoicexpress_woocommerce_settings_tabs( $tabs ) {
	$tabs['temp'] = array(
		'title'    => 'TEMP',
		'sections' => array(
			'temp_one' => array(
				'title'       => 'Section one',
				'description' => 'Section one description',
				'fields'      => array(
					'hd_wc_ie_plus_section_one_field_one' => array(
						'title'       => 'Field one',
						'description' => 'Field one description',
						'type'        => 'text',
					)
				),
			),
		)
	);
	return $tabs;
}