There are three main types of user interface design: Graphical User Interface (GUI): In this type of design, users interact with visual representations, such as icons on a PC desktop, to open programs and initiate activities. Voice User Interface (VUI): By speaking commands or questions, users are able to interact with a variety of products and services. The most commonly used VUI is associated with “smart assistants” such as Alexa or Siri. Gesture-Based Interfaces: In this type of interface, users interact with products and services through bodily motions in virtual 3D spaces. Examples include virtual reality gaming or training exercises.