You may also have to supply a copy of a Medicare Card, Centrelink Card, or a recent utility bill. Stipulations change from one licensing jurisdiction to another, but usually it will consist of emailing a copy of a passport, National Identity card, or drivers licence. When you sign up to a licensed pokies site, you will usually have to supply some ID within your first month of registering. If you are playing for real money, expect an identification check somewhere along the line. Licences can be removed if online casinos don't adhere to strict security measures.
Making sure customers are of legal age and are who they say they are is important for casinos.