I have already added a customer to a transaction I started, can I still edit the customer’s information?

Sure! Users can edit their customer’s information at different points of the transaction by clicking the “Edit Details” button. It can be done: 

  1. In the “Customer View” section from the register page
  2.  In the beginning of a transaction before adding the customer to the sale and
  3.  In the checkout page before payment

Edited information is automatically updated in your WooCommerce users database also.