This article explains how to type on your phone with your voice. This works on all devices that run Android, regardless of manufacturer (Google, Samsung, etc.).
Hands-Free Typing: A Guide to Enabling Voice Text on Android – Speech Recognition on Android Phone
Android phones come with a speech-to-text converter that lets you dictate text messages, emails, and other text you normally type. It's enabled by default and should work with any app that accepts text input.
Tap the text box to bring up the keyboard.
Tap the microphone icon.