Screenshot: Pranay Parab
Siri is also responsible for showing you relevant app suggestions when you fire up Spotlight search on iOS. If you want to hide an app or its content from Spotlight search results, you can go to Settings > Siri & Search on your iPhone and scroll down until you locate the app. Tap the app’s name and disable Learn from this App to stop using this app’s usage data for suggestions. You can also disable Show App in Search and Show Content in Search to hide it from search results.
Finally, to completely hide the app from Siri, you can disable all other options on this page, which includes Show on Home Screen, Suggest App, and Suggest Notifications.
