Bluetooth keyboard connected but not working on iPad

Hello denachaya.

Thanks for reaching out to Apple Support Communities. We see that you are having trouble typing with your Bluetooth keyboard. We will be glad to assist.

Let's take a look at the following steps which can help:

1. "If you previously connected your Bluetooth accessory to your iOS or iPadOS device, unpair the accessory, put it back in discovery mode, then try to pair and connect it again.
2. If you can pair your accessory with some devices but not your iOS or iPadOS device, unpair the accessory from your other devices. Then try to pair with your iOS or iPadOS device again.
3. Check with the accessory manufacturer to make sure that your accessory supports your iOS or iPadOS device.
4. If you still have any of these issues, contact Apple Support: 

• • You can’t turn on Bluetooth or the setting is grayed out.
  • You can’t connect any Bluetooth accessories with your device.
  • The accessory manufacturer confirmed that your accessory is working correctly."

If you can't connect a Bluetooth accessory to your iPhone, iPad, or iPod touch

Cheers.