hi @faithhopelove, the filing can be done online - https://www.ato.gov.au/Individuals/Tax-file-number/Apply-for-a-TFN/
they will mail you the TFN to the address you provide. the site says it can take up to 28 days but i believe mine came in less than 2 weeks.
as far as i recall, there isn't much requirements. i think i only submitted my passport and visa details. though i can't really recall now.