Add to product details page

functions.php

add_filter('woocommerce_product_tabs', 'add_my_tab');

function add_my_tab($tabs){
	$tabs['details_tab'] = array(
		'title'     => 'New Tab',
		'priority'  => 1,
		'callback'  => 'tab_content',
	);
	return $tabs;
}

function tab_content(){
	global $product;
	echo $product->get_description();
}