how to add username and password field in commerce order I am new with Drupal and I am willing to learn more.

now, I am creating a project and I am using the drupal commerce.

In the check-out process, In default, for unregistered users, it has the email field and others field. I just want to add username, password and password confirm fields so that the anonymous user will register then he can pay for the item he cheked-out.

but the problem is I don't know how to add those fields.

I have also checked the Checkout Rules (Create a new account for an anonymous order), I think the process of creating the user is done here, but I don't know how.

Does anyone can help me in my case?
any help will be appreciated...

thanks in advance ...
This is currently being handled via the Rules module. The rule that is enabled by default creates the user via the "Create a new account for an anonymous order" rule. There is no way to insert a password in here but is up to the user to open the link in their email and set their password manually.