How can I add extra field on wp commerce checkout form

It is very much easy to add an extra field to the wp e-commerce checkout form
You can add, modify, and re-order of this form.
Just go to store admin then setting.
click on the Checkout tab and here you can make your desired form.

This is the most important thing that you would like to sent the form data to your email and customer email address.
For this go the setting and click admin tab. Here you can customize the email form of customer and admin. Type your massage and use the tag for dynamic data.

You can create more tag to fullfill your requirement. Suppose you create another two field in checkout page. And you want to sent this filed value to your customer and admin email.

To create more tag you will have to add the code to this wp-e-commerce/transaction_result_functions.php file.
This is an example that I create

This group of code add the above php file at your common sense.

In admin panel I use the tag name %std_name% and %std_sch_name% for Student name and Student School name.

For the value of $std_name and $std_school you will have to query above this group of code.

http://getshopped.org/forums/topic.php?id=11730

The database table wp_wpsc_checkout_forms will help you to better understand. For more customized your emial from you can Contact with us.