Administrator comment an order and email the customer

Hi all,

I am looking for a solution that the administrator can comment an order, and the customer can get the comment with the order information.
Right now if I want to do so I have to find the order mail and reply it to customers, which makes it inefficient. -_-

Is there any extension can solve this?

I am not sure if I understood what you want or missing.
Because in OpenCart Backend whenever you open an order (not edit), you can add a comment you like and send the comment with the current status to the customer (notify).

Not standard is, to send the whole order (info) again with a (additional) comment.
To do so, you need an Extension like this: Send Order Copy with comment