Voice Commands control and format the document you are dictating. Typically, a voice command starts with "TalkType" once you start dictating and then the action you wish to perform.
How to Find a List of Available Voice Commands
You can easily find a list of available voice commands from TalkType by opening the application and then clicking on the icon that looks like a person speaking in the top right-hand corner.
From here, you can see all the available voice commands you can use when editing and formatting your document.