Mail New User

This module enables admin users to modify the welcome email subject and body at
the moment at which the email is about to be sent.

At the user creation page (admin/people/create), there is a checkbox "Notify
user of new account". When the checkbox is not checked the mail contents are not displayed. When this is checked, the contents of the welcome email normally at the Account settings page (admin/config/people/accounts) is displayed and can be changed. Note that the "Notify user of new account" button is not new; what is new is the ability to directly edit the contents of the sent email.