Siri analyzes how you use your device to provide personalized suggestions and better search results using local, on-device processing
Siri learns how you use your devices in order to personalize your experience. Using information stored on your device, such as your Safari browsing history, emails, messages, and contacts, as well as information contributed by other installed apps, Siri can provide suggestions in Spotlight, Look Up, News, Photos Memories, and more using local, on-device processing. You can see the full list of features that Siri personalizes in the Siri section of System Preferences, under Siri Suggestions & Privacy.
Personalization is synced across your devices with end-to-end encryption
Siri securely syncs this information among your devices, to make your experience consistent on all of them. This sync is done using end-to-end encryption.
To make suggestions and search results more relevant, some information is sent to Apple and not associated with you
In some cases, such as when you use Siri Suggestions in Spotlight, Look Up, or Safari, generalized topics of interest that Siri has learned may be sent to Apple to make your searches more relevant. These topics of interest (for example, cooking or basketball) will help to give you more relevant search results, and we use privacy-friendly techniques to disassociate these topics of interest from you.
In addition to these topics of interest, when you perform a search, your device sends your search queries, suggestions you have selected, and related usage data to Apple to process your request. This information is not associated with you. Search results that show files and content on your device will not be sent.
If you have Location Services on your device turned on, the location of your device will be sent to Apple to provide more relevant recommendations. To provide you with more relevant music and video suggestions, if your device can access music or video subscription services, then information such as the names of the subscription services and types of subscriptions may be sent to Apple. Your account name, number and password will not be sent to Apple. Location, search queries, your interests, and usage information sent to Apple will only be used by Apple to make Suggestions more relevant and to improve other Apple products and services.
To improve search results, words and phrases collected over time from common searches may be forwarded from Apple to a web search engine.
You have choice and control
If you do not want Siri Suggestions to send your information to Apple, you can turn off Siri Suggestions. You may do so under System Preferences, select Spotlight and deselect the checkbox Spotlight Suggestions and Spotlight Suggestions in Lookup. Safari Suggestions can be turned off in Safari. Open Safari, select the Safari menu and choose Preferences, click on Search, and toggle off Include Safari Suggestions.
You can stop apps from contributing information to personalize Siri. Go to System Preferences, click Siri, then select Siri Suggestions & Privacy. Deselect the checkbox for an App.
You can turn off Location Services for Siri Suggestions. To do so, open System Preferences, click Security & Privacy, select Location Services in the Privacy tab, click the lock to make changes and enter your password, select Details next to System Services, and deselect Location-Based Suggestions. If you turn off Location Services on your device, your precise location will not be sent to Apple. To deliver relevant search suggestions, Apple may use the IP address of your Internet connection to approximate your location by matching it to a geographic region.
If you do not want Siri personalization to sync across your devices, you can disable Siri under iCloud settings.