Checkout Completion Rules
Drupal Commerce defines several default checkout completion rules that perform the following operations when an order in checkout first reaches the checkout completion page:
- Updates the order status to the default status of the Pending state (typically the matching Pending status).
- Assigns an anonymous order with a known e-mail address to the appropriate user account -or-
- Creates a new user and sends the new account e-mail notification to the customer.
- Send an order notification e-mail to the customer.
You are free to customize these defaults rules, disable them entirely, and add your own rules to address your business logic pertaining to what must happen on checkout completion. Note that payment may not have been completed at this time; it may still be pending or it may have been submitted as an authorization awaiting a later capture.
If you have business logic that depends on payment being completed, you should add rules to the When an order is first paid in full event instead.

