Q: How to add a custom field of Ajax Quick Checkout
A: Very simple. You need to add it first in the opencart admin panel. Go to Sales -> Customers -> Custom Fields. Add your field there. Then return to the Ajax Quick Checkout set the display options and click save. Remember to re-save the settings for the field to display.
Q: Hi, why do I see orders with default email in them.
A: The default email will show if the customer did not enter his email and he abandoned the order. The order is created on the first load as it is the way the checkout needs to work to follow the opencart standards. So this is just a lost order for you. You can delete it if you like.
Q: Hi, I have a lot of Abandoned orders - why so .
A: Opencart default checkout system create an order_id on the first step when you add your information. This order_id is a required parameter for shipping and payment methods to load. In Ajax Quick Checkout we display on the first page all the steps and that is why we are required to create order_id on the load. So everytime a customer visits your checkout page - this means he will create a new order. If he leaves your checkout page - he will abandon his order.