Siri support for third-party applications requires iOS 10 or later , as well as installing the third-party applications that you want to use that are compatible with the voice assistant. Apart from that, you'll need to manually enable Siri support for third-party applications.
How to enable Siri support for third-party applications on iOS
- Open the "Settings" app in iOS
- Go to the "Siri" section and then choose "Application Support"
- Move the switch to the on position that is next to each application in which you want to enable Siri compatibility