You will normally need to apply directly to your chosen education provider. Contact the institute or visit their website for more details on the procedure.
You may also be able to apply through a recognised ENZ agent.
If your course is less than 12 weeks long, you’ll need only a visitor visa to come to New Zealand. However, if you plan to study for more than 12 weeks you’ll need to apply for a student visa by post or at your nearest Immigration New Zealand Office.