Twitter userJay Prakashshared screenshots of the feature.
It needs to be enabled in the phone’s app tweaks before it can be used.
Once it’s toggled on, a Record button appears in the UI while making or receiving a call.

Jessie Casson/Getty Images
It’s also limited to countries and regions where call recording is legal.
In the US, the legality of call recording varies depending on where you live.
Call participants are notified they’re being recorded before the call begins, according to Google’s support page.

Jay Prakash
Their rig must run Android 9 or higher and have the latest version of the Phone app installed.