"With the release of iOS 12, many third-party developers have been updating their app to support the Siri Shortcuts suggestions feature which enables actions you take in those apps to be surfaced to Siri.
These suggested shortcuts will either open deep into the app to show you something you were looking at, or if the developer has taken advantage of new Siri APIs, they can perform a task for you from within the Siri interface.
Once you've gone about your day and used the app, you should start to see these actions suggested by Siri on the lock screen or in Spotlight search.
Plus, if you get the dedicated Shortcuts app that Apple has just released, you can also add multiple of these and kick them off in order. Any suggested shortcuts included in your custom shortcuts will work entirely in Siri, which is a plus over some native Shortcuts actions that require opening the app to continue."