A confirmation that settings or action is acceptable. For example, a dialog box has an Ok button, and when pressed, any settings in that window are saved. If the window has no settings, Ok confirms you read the message.
The picture below is an example of an error message in Microsoft Windows with an OK button. In this example, the OK confirms that the user has read the error message.
Cancel, Operating system terms, Option, Push button
If this button is selected (bold), you can press the Spacebar or the Enter on the keyboard to select the button without using the mouse. If there are multiple buttons, you can press the Tab to move between buttons.
