Your tax file number (TFN) is your personal reference number in the tax and super systems.
Your TFN is an important part of your tax and super records as well as your identity, so keep it secure.
Your TFN is yours for life. You keep the same TFN even if you change your name, change jobs, move interstate or go overseas.
You don’t have to have a TFN, but without one you pay more tax. You also won’t be able to apply for government benefits, lodge your tax return electronically or get an Australian business number (ABN).
How to apply
If you’re an Australian resident, you can apply for a tax file number (TFN) in various ways but the easiest and often the most convenient is via an online form and provide proof of identity documents at your local Australia Post office.