I am trying to display customer order details as i have implemented all the steps mention in the tutorial https://www.wpblog.com/display-woocommerce-customer-order-details/ but still i am not having the actual output.

I have taken order id as same implemented there but not having a exact output that shown. 
$order_id
$order_meta = get_post_meta($order_id);

Hi,

We're a french speaking community. Only french written topics authorized on forums.

I move your topic into the english speaking section, but you may not have pertinent answers here ...

Consider use an english speaking community, you'll find many on the web.