IELTS

International English Language Testing System (IELTS) is an English language exam that is required to be taken by international candidates considering studying or working in a country where English is the main language of communication. Most popular countries where IELTS is accepted for university admissions are UK, Australia, New Zealand, US, Canada. The exam mainly measures the ability of test-takers to communicate in the four basic language skills listening, reading, speaking, and writing.
There are no minimum IELTS eligibility criteria for IELTS 2017. Any person who wishes to pursue education or work opportunities in an English speaking country can apply for the IELTS test.

Hi Dhanusha, an IELTS score will not necessarily grant you work permit though it is a requirement. Work permit rules are different with countries and you must meet a lot of requirements. But firstly you must be offered a job by an employer. Unless you are qualified and have some work experience chances will be slim. IELTS is a visa requirement. Also when you say permanently, no you cannot, you have to apply for a PR which is again a different process, and to apply for a PR you must have worked in the foreign country for many years and meet the requirements of a resident. Why don't you consult an immigration agent? you will get better advice for your query. This portal is generally for higher education.