In order management Customer details can be viewed or edited;
Firstly, press on the orders tab in the right side of the screen:
New information will be presented about orders. In the orders page select one order to check the client details:
Customer details can be viewed, or edited by pressing on the pen icon on the right side of the screen:
A new window will pop up with customer details:
Customer can be changed if needed, press on the Customer field and choose a different customer from the drop down list, after that press Save;
New customer can also be added;
How to add a new customer can be found here;