Google Assistant “Hey Google” Trigger Arriving on Phones
Google has begun the process or rolling out a combination app and server-side update that enables the “Hey Google” hot word on Android phones. Once complete, you can activate Google Assistant by using the trigger just like you can on Google Home.
To this point, the only hot word that Assistant would respond to on your phone has been “OK Google”. When Google Home was released last year, Assistant on the smart speaker would respond to this too as well as “Hey Google”. It is unclear why it took so long to get to phones but it is slowing rolling out to users now.