Please know that to manage the orders in admin panel we have to follow  below instruction

Managing orders

When a customer goes through checkout, the information on their order is automatically transferred to the Orders section for you to keep track of. In the administration, you can view all of the orders made on their site, manually add orders, or edit the details of existing orders.

Viewing order details

The Orders section is located under Sales > Orders. On this page, every order ever made from the store is listed in detail.

The following details are displayed for each order on the list:

                Order ID: a number assigned to an order by OpenCart during the checkout confirmation

                Customer: the name of the customer that made the order.

                Status: update of the status of the order. After the order is initially created the status will be "Pending". The default options are                 Missing Orders, Canceled, Canceled Reversal, Chargeback, Complete, Denied, Expired, Failed, Pending, Processed, Processing,                 Refunded, Reversed, Shipped, and Voided.

                Total: the total price of the order.

                Date Added

                Date Modified

With the orders included in the list, there is an option to edit, insert, delete, search, or print an invoice of an order.

Searching for an order

The "Filter" button under Action helps you find orders based on