To resend the confirmation email on a shipment, you will first need to go to Shipments, at the top:
Next, first locate the orders you would like the confirmation email to be resent and select them. Once they are selected, simply go to the top bar and click on the Resend Confirmation Email(s) button.
A new pop-up window will come up, asking you to confirm your choice.
As soon as you click on Send Email, the confirmation emails will be sent.