The battery on my iPad 9th generation lasts about 2-3 hours. What is the cause or fix?

Hi Apple42me,

Thanks for coming to Apple Support Communities for help today.

You can see some tips here that can help with Maximizing Battery Life and Lifespan

These include:

1. Update to the latest software
2. Optimize your settings
3. Turning off Background Activity for apps.
4. Using Wi-Fi over instead of cellular data.

You can also have Apple Support run diagnostics on your battery.

Have a fantastic day!