You can use > Accessibility > Hearing Devices, you need to pair them with iPad.
If your hearing devices are already paired to another nearby device, such as a Mac or iPad, make sure Bluetooth® is turned off on those devices. (When you finish pairing your hearing devices to your iPad, you can turn Bluetooth on again on those devices.)
On iPad, go to Settings > Bluetooth, then make sure Bluetooth is turned on.
Go to Settings > Accessibility > Hearing Devices.
Turn your hearing devices off and back on again.
If you’re unsure how to turn them off, refer to the instructions that came with them, or check with the audiologist who helped you set them up.
When their name appears below MFi Hearing Devices (this could take a minute), tap the name and respond to the pairing requests.
Pairing can take as long as 60 seconds—don’t try to stream audio or otherwise use the hearing devices until pairing is finished. When pairing is finished, you hear a series of beeps and a tone, and a checkmark appears next to the hearing devices in the Devices list.
You need to pair your devices only once (and your audiologist might do it for you). After that, your hearing devices automatically reconnect to iPad whenever they turn on.
In Settings: Go to Settings , add it to route audio calls to a hearing device.
To troubleshoot issues you have using your hearing devices with iPad, see the Apple Support article, Accessibility features for hearing on iPad