To create a new user for your store, go into the Admin Interface, click the Users tab, and click the New User button.

Users tab

The three mandatory fields (“Email”, “Password” and “Password Confirmation”) and Roles checkboxes (“Admin” and “User” those are created by Spree default, there is possibility to extend Roles by backend work).

Add new User

Editing existing user

Once you have created an account you are redirected to User edition page about which you can find more here.