To apply for rent assistance, you need to be receiving an eligible payment from Centrelink, such as JobSeeker or the Age Pension. You can submit your application online through your Centrelink online account or via the Express Plus mobile app. If you prefer, you can also visit a Centrelink service centre for assistance. Make sure to have your rental agreement and proof of rental payments ready, as you may need to provide this information. For more details, you can check the official Services Australia website.