Change default order filters to Pending & Processing

snippet.php

/**
 * Change default filter of orders in WP admin
 * add this to your functions.php file
 */
add_action( 'admin_menu', 'change_default_order_filter', 99 );
function change_default_order_filter() {
	global $submenu;
	if (isset($submenu['woocommerce'])) {
		$submenu['woocommerce'][1][2] = 'edit.php?post_type=shop_order&shop_order_status=pending,processing';
	}
}