Citizenship by descent - which requires an applicant to have at least one parent being an Australian citizen at time of birth.
Citizenship by conferral - which requires an applicant to be a permanent resident within the meaning of the Australian Citizenship Act (Cth) 2007 and meet the residence requirements, including complex cases where special residence requirements may be relevant.
Citizenship for applicants adopted under the Hague Convention on Intercountry Adoption or a bilateral arrangement - which requires the adopter(s) to be Australian citizens at time of adoption and to have resided lawfully in Australia for a certain duration before make an application for such method of citizenship acquisition.