To migrate to an english speaking country, one needs to pass an english proficiency test.
IELTS test is of two types:
IELTS General Training test
The former test is taken by people who wish to to carry on their higher studies in an english speaking country. The pattern reflects the language used in the academic courses in such countries and ensures that you are ready to start with your studies there.
While the latter test is taken by people who wants to permanently migrate to countries like Australia, UK, Canada and New Zealand.While in other countries, General Training IELTS test score can help you to take part in training programs or attain a work experience.
Moving forward, both the tests are divided into 4 modules, namely, Listening, Reading, Writing and Speaking.
All these modules individually carry 9 bands and their combined average gives you the final band scores. Therefore, it is necessary to score well in all the modules and you cannot skip any of these tests.