Apple has published an article about “Our Longstanding Privacy Commitment” with Siri.
From the article: At Apple, we are committed to protecting user data, and our products and features are built from the ground up with innovative privacy technologies and techniques. Privacy is a foundational part of the design process, driven by principles that include data minimization, on-device intelligence, transparency and control, and strong security protections that work together to provide users with incredible experiences and peace of mind. This applies to all of our products and services, including Siri, which has been engineered to protect user privacy and is the most private digital assistant.
Apple has never used Siri data to build marketing profiles, never made it available for advertising, and never sold it to anyone for any purpose. We are constantly developing technologies to make Siri even more private, and will continue to do so.
You can read the entire article to see how Apple says Siri protects user data.
