Email addresses use a standard formula. They are always separated into two parts by the @ symbol.
The first part of the email address usually identifies you in some way. You might have your real name for the first part of your email address, or you could use a handle or a nickname that your friends and family will recognise.
The second part of an email address usually comes from your webmail provider or the internet service provider you use. If you're emailing someone and they, or their business has a website, you'll see that the second part of their email address uses part of their website address.
This gives a standard formula for all email addresses which will look something like firstname.surname@somewhere.com.au or yournickname@somewhere.com.au
Some people have two or more email addresses, one just to give to friends and family, one for a work or student email account, and sometimes another email address that can just be used to give to people you don't know—like when you sign up for email newsletters or for communicating with online businesses you don't know.