对于这三种可能性：

如果您真的想按订单进行，则必须使用挂钩：

woocommerce_new_order

但是，我建议您使用挂钩：

woocommerce_order_status_completed

这将确保在您发送then信息时完成订单。

要在计费前捕获信息，您可以始终使用：

woocommerce_before_checkout_billing_form

如果这仍然不起作用，您可以查看挂钩列表：

https://docs.woocommerce.com/wc-apidocs/hook-docs.html

然后，您只需执行以下操作：

add_action( \'woocommerce_order_status_completed\', \'wc_send_order_to_mypage\' );
function wc_send_order_to_mypage( $order_id ) {
$shipping_add = [
            "firstname" => $order->shipping_first_name,
            "lastname" => $order->shipping_last_name,
            "address1" => $order->shipping_address_1,
            "address2" => $order->shipping_address_2,
            "city" => $order->shipping_city,
            "zipcode" => $order->shipping_postcode,
            "phone" => $order->shipping_phone,
            "state_name" => $order->shipping_state,
            "country" => $order->shipping_country
        ];
//from $order you can get all the item information etc 
//above is just a simple example how it works
//your code to send data
}

由于最终目标是拥有自己的支付系统，我建议您查看本教程，该教程解释了如何集成自己的支付网关

https://www.skyverge.com/blog/how-to-create-a-simple-woocommerce-payment-gateway/