A switch is a visual toggle between two mutually exclusive states — on and off.
Consider tinting a switch to match the style of your app. If it works well in your app, you can change the colors of a switch in its on and off states.
Use switches in table rows only. Switches are intended for use in tables, such as in a list of settings that can be toggled on and off. If you need similar functionality in a toolbar or navigation bar, use a button instead, and provide two distinct icons that communicate the states.
Avoid adding labels to describe the values of a switch. Switches are either on or off. Providing labels that describe these states is redundant and clutters the interface.
Consider using switches to manage the availability of related interface elements. Switches often affect other content onscreen. Enabling the Airplane Mode switch in Settings, for example, disables certain other settings, such as Cellular and Personal Hotspot. Disabling the Wi-Fi switch in Settings > Wi-Fi causes available networks and other options to disappear.
For developer guidance, see UISwitch.