IELTS is a language proficiency test that is mandatory for admissions seekers in the countries- UK, Australia, New Zealand & Canada. It measures the ability to communicate in English across all four language skills- listening, reading, writing and speaking for people who intent to study or work where English is the language of communication.
IELTS is also recognized by professional bodies, immigration authorities & other government agencies. It is jointly managed by university of Cambridge ESOL Exams,
British council and IDP Education
Australia : IELTS Australia