For devices that support Apple Intelligence, Image Playground should be automatically installed on the device when Apple Intelligence has been successfully enabled from iPad settings:
Settings > Apple Intelligence & Siri > Apple Intelligence - set to ON
If the Image Playground App has been deleted from a supported device, it can be reinstalled from the Apple App Store:
https://apps.apple.com/app/image-playground/id6479176117
It follows that your device must support Apple Intelligence - and be set to a supported language in a country where this new feature is available:
How to get Apple Intelligence - Apple Support