A toggle is a switch that enforces two mutually exclusive states (on or off). When you toggle it, you can only choose one of the two. Toggles are most often found in options menus, where users are able to select the settings they want. They also appear in some hardware, like the caps lock key on a keyboard.
A good toggle design should use a clear and meaningful label to indicate the current state of the control. In particular, it should describe the action that will take place when the toggle is switched to the active state. For example, “Show sent messages.” In addition, designers should avoid using ambiguous language for the toggle, such as “neutral” or “undefined”. Instead, it is better to use simple words that are familiar to most users.
Toggle switches should look similar to sliders and utilize visual cues such as movement and color to help users distinguish between the on and off states. When users see a more pronounced, saturated color for the active option, they are able to quickly and accurately decide which one to press. However, when a more subtle version of the toggle is used, they are unable to understand which option is active.
While a toggle is an effective tool for letting people manage the state of something, it shouldn’t be used for things that require more than just an on or off decision. Instead, consider using a checkbox or other form of radio button, as these can be made to support multiple outcomes.