Everyone who works in Australia needs a Tax File Number (TFN). This means that if you get a part-time or casual job while you are at school you will need a TFN. Your TFN is free. It is yours for life. The TFN you get for your part-time job at school is the same TFN you will have when you are working in your adult life. When you work your employer deducts tax from your wages and pays it to the Government on your behalf. Your employer also pays superannuation into your superannuation account on your behalf. Your superannuation is savings fund for your retirement. Your tax and your superannuation are linked to your TFN. At the end of the financial year (30th June) you can do an Income Tax Return. You may even get some of the tax you paid during the year back from the Government.
Read the article on Job Jumpstart about paying tax.
There are three ways you can apply for a TFN: