Your username can take a couple of different formats.  For apps and services that support Office 365 standards, your username is the same as your email address.  For other apps and services, for example Moodle, your your username is the part that comes before the "@" symbol.

In situations where more than one person has the same name, we use the initial of your first name.  If there's a third person with the same name, we omit the "." between your initial and the surname.