IOS – view or export or clear Siri’s interaction history

Taken from the privacy file displayed when turning Siri on - off.

You may choose to turn off Siri or Dictation at any time. To turn off Siri, open Settings on your iOS device, tap General, tap Siri, and slide the Siri switch to “off”. To turn off Dictation, open Settings, tap General, tap Keyboard, and slide the Enable Dictation switch to “off”. If you turn off both Siri and Dictation, Apple will delete your User Data, as well as your recent voice input data. Older voice input data that has been disassociated from you may be retained for a period of time to generally improve Siri, Dictation and dictation functionality in other Apple products and services. This voice input data may include audio files and transcripts of what you said, related diagnostic data, such as hardware and operating system specifications and performance statistics, and the approximate location of your device at the time the request was made.