Email that is stored on the server can be accessed via an online portal known as Webmail.
You can access Webmail by going to mail.yourdomainname.com.au in your web browser and logging in using the username and password for the account.
Username: Your full email address
Password: The corresponding password
See https://portal.webclick.com.au/knowledgebase/33/Horde-WebMail for tips and tricks for using webmail.