If you need to resent an order notification email to client navigate to:
 - Dashboard

 - client Orders (from WooCommerce Status)

- Orders
- select the customer name (name is a link)

The Order will appear as per below

 - Right side has Order Actions

 - click Resend Order Notification

There is also an Order Notes area just below on the right side

Here you can make PRIVATE notes for internal use or send email messages to customers (ie great for additional order updates or extra correspondence if required)