A root store administrator and an administrator with administrator management permissions can delete any user profile from the user list. A store administrator with user management permissions can delete customer accounts only.
To delete an account:
Open the User List in your store's Admin area.
Click the Trash icon opposite the account you want to delete.
NOTE: You can delete several accounts simultaneously.
Click Save changes to confirm account deletion.
NOTE: The store's order history remains unchanged even for a deleted customer account.
Related pages:
Force a User to Log Out
Operate as a User
User Import/Export