All users can use the built in email function to email others listed on the various rosters in your organization account. The function is accessed under the menu "Email" -> "Send Email / Text".
Administrators have access to email to all potential recipients, including the ability to select recipients based on a variety of criteria or simply by name. The email permissions group grants specific individuals complete access to the email function as if they were an administrator.
Officials can use the email function but only in a limited capacity. By default, Officials can only email up to 3 other selected individuals or the other members of a crew on a game he/she is working. The number 3 can be customized on the configuration page. Access to the email function by officials can also be disabled. Officials do not have the option of choosing officials by all of the criteria available to administrators, but only by name or by game.
School/Team contacts also have access to the email function in some cases but their access is more limited if the options to allow them to see the contact info for officials is disabled.