With the iOS 16.5 beta, Apple is working to improve Siri's functionality, and there is a new option to start a screen recording with the voice assistant. As noted by 9to5Mac, you can now say "Hey Siri, start a screen recording" to use the Screen Record feature.
Using this command will cause the iPhone's screen to be automatically video recorded until you tap in to turn it off or activate Siri and say "Stop the screen recording."
Note that the wording of the screen recording command needs to be fairly specific as something like "take a screen recording" results in a screenshot rather than the video recording function. Siri has been able to take a standard screenshot for quite some time, but the screen recording function is definitely new in this beta.
In prior versions of iOS, when you ask Siri to start a screen recording, the voice assistant does a web search or says you have no such app installed.
iOS 16.5 was provided to developers today and it should be coming to public beta testers later this week. Aside from the Siri screen recording feature, Apple has also added a Sports tab in the Apple News app. No other new additions have been found as of yet.
Source: Macrumors