could i take admission in 12thclass in australia

HI Suryaranjan, to apply to an Australian School you must send them your documents. you need to clear IELTS before you land there. Before you begin applying you will have to identify an international school for yourself and find out the term dates. The various states in Australia have different term

Yes you can take admission in 12th class in australia, but just go through the subjects and specialized syllabus in school because the area of learning is different in australia as compare to India

yes u can do that