Modify user submitted form data before it is saved an emails are sent
You maybe able to add a submit handler or validate handler.

How do I add an additional submit handler in commerce checkout form?

https://stackoverflow.com/questions/15375616/how-to-use-form-validation-in-drupal-7

See the form examples >  https://api.drupal.org/api/examples/form_example!form_example_tutorial.inc/7