How do I setup airpods pro 2 for hearing aids

In order to use the hearing test and hearing aid function, three things must be true. 

1. Your iPhone must be updated to 18.1. Here are instructions to update. Update your iPhone or iPad - Apple Support
2. Your AirPd Pros 2 must be updated to their latest firmware. Here are instructions to update. About firmware updates for AirPods - Apple Support
3. You Apple Account must be registered in a country that supports the hearing aid feature. Check your country here.  AirPods Pro 2 - Hearing Health Feature Availability - Apple

Once these three requirements are satisfied, place the AirPod Pro 2s in your ears. Go to Settings > your AirPods. Tap Hearing Assistance. If you haven't taken the Hearing Test, tap Take a Hearing Test.