A passport is generally the preferred and recommended identification document when registering for the IELTS exam, especially for international students. However, if you do not have a passport, other forms of government-issued identification may be accepted, depending on the test center's policies. It’s important to check with your specific test center to see if they allow other IDs, such as national identity cards or driver’s licenses.
When registering, always ensure that the ID you use matches the personal information you provide in the registration form, including your IELTS exam date and test center. If you're unsure about how to apply for IELTS exam without a passport, contact the test center beforehand to confirm the acceptable forms of identification.
Note that if you are taking the IELTS exam in a country where your passport is required but you don’t have one, you may need to apply for one before proceeding with your registration.