Your school can have you set up with a HeadMaster desktop account. This means that you have a copy of HeadMaster installed on your desktop PC or laptop. You log in to that local install of HeadMaster, and perform your tasks. For more information, see the HeadMaster User Guide.
Your school can have you set up with a HeadMaster OnDemand account as your primary means of accessing HeadMaster. With HeadMaster OnDemand, you have full access to your HeadMaster data via the internet. With HeadMaster OnDemand, you always have the latest software version and you're viewing and editing your live data. For more information, see the OnDemand User Guide.
Your school can have you set up with a HeadMaster Online account in addition to your desktop account. This means that you have view-only access to your HeadMaster information, typically via a link on your school's website. Your information that you view is current with the latest HeadMaster upload that your school has performed. All you need is an internet connection and you can log in from anywhere on most any mobile device. For more information, see Log into HeadMaster Online.
If you're still not sure about what kind of HeadMaster account you have, please consult your school's HeadMaster administrator.