Drupal Commerce: Allow anonymous users to choose their username on checkout The default setup includes a single option in the "Account Information" pane which allows for an email address. The user's username is then derived from that.

I would like to add another field for "Username" where the user can enter their own username, instead of having it generated for them automatically based off of their email.
Theres a sandbox project here that you will need to download with git that looks like a complete sign up form.

Theres also Commerce User Profile Pane that allows you to choose the fields in the pane. Ive not used it before, but looks like a good place to start.