"To get a Customer Reference Number you do an application through Centrelink. It's a unique identification number that's applied to you and also to your child. If you've used Centrelink services before then you'll already have a CRN, or a Customer Reference Number. If you haven't then you need to go to Centrelink in person and get a CRN. You'll also need one for your child, so it's important to bring personal documents relating to yourself and your child."