Eligibility
The most common pathway to Australian citizenship is by conferral. You must hold a permanent resident visa and have lived in Australia legally for at least four years before applying. During those four years you cannot have been absent from Australia for more than 12 months in total, and no more than 90 days in the 12 months immediately before you apply.
Applicants must be of good character, which generally means having no serious criminal convictions and having abided by visa and citizenship laws. You should also maintain a close and ongoing link with Australia and plan to continue living there. Basic English knowledge is required.