Some other carriers do this and it’s a nice welcome gesture at almost no cost to the provider. There’s a programmable key that could be set for push-to-talk (app required?) or it can invoke any app through a protracted or double-press per your alternative of the setting. The choices for the ‘Programmable key’ are in the principle Android Settings. I set the necessary thing to start Google Assistant as a outcome of the phone just isn’t designed for Assistant’s standard ‘Hey Google’ voice activation.