IELTS Tests are suspended due COVID-19. If you are registered for a test that has been cancelled we have emailed you with refund/transfer instructions.See the COVID-19 page for details.
IELTS Official Test Centre

Anyone who is at least IELTS band 4 now.

It is not necessary to have done an IELTS test before, but you need to be capable of A2 (Elementary) English to take the pretest.

If you are not sure, you can take a quick quiz online.