It depends where you are in the world. In many places, all service providers/carriers fully support casino mobile games. However, not all service providers support 3rd party app downloads.
Until recently in the US, you couldn’t download casino apps from the Google Play Store, so the apps needed to be downloaded from a third party website – such as the online casino itself.
As for your service provider, it may or may not support third party apps. If you experience any issues related to downloading and installing apps, follow the guidelines provided by the online casino itself.