How can you get this online anybody know
An IELTS test is usually for non-native speakers of English to prove their level of English for immigration or University entrance. The test is not normally done online, but at an exam centre, with listening of 30 minutes, reading and writing an hour each and then a 15 minute speaking interview. If you are an English native speaker then the test should be unnecessary.
Can’t answer on where to do it online, should be possible in person these days, can’t really see how it could be done online as it’d be too easy to get assistance. However, it most definitely is necessary now even for native English speakers, has been for years when they removed the exemption for anyone who’s primary education was conducted in English so now you have to prove you can read/write/speak English even if you’re English.