Google Voice Typing is pre-installed on your Hot Pepper phone. To verify that it is enabled, please go to Settings > System > Languages & input > Virtual keyboard (under Keyboard & inputs). You should see both Gboard and Google voice typing on this page. If both are enabled, you will see Multilingual typing under Gboard, and Automatic under Google voice typing.
When the keyboard appears, tap on the microphone icon in the upper-right corner of the keyboard display. Once tapped, your voice will be transcribed to text. Tap on the microphone icon again to stop voice typing.