Hi,
Note that we don't recommend doing this, for obvious security reasons.
In the file components/com_hikashop/controllers/order.php in the function isLogged you can add a return true; at the beginning.
This will prevent the controller from redirecting to the login form page when the current user is not logged in with the user account of the order or is not logged in.
Then, in the file administrator/components/com_hikashop/classes/order.php in the function loadFullOrder you can add $checkUser = false; at the beginning.
This will allow the loading of the data from the database for the orders even if the current user is not logged in or not the user of the order.