When we talk about 'voice' in sentences, we mean whether a sentence is written in the active voice or the passive voice. In the active voice, the subject of the sentence performs the action. For example, 'John threw the ball.' In this case, John (the subject) is doing the action of throwing. On the other hand, in the passive voice, the subject of the sentence is acted upon by the verb. For example, 'The ball was thrown by John.' Here, the ball (the subject) is receiving the action of being thrown. Switching between active and passive voice can alter the tone and focus of a sentence. Active voice tends to be more direct and energetic, while passive voice can sound more formal and impersonal. Active voice is often used for clarity and engagement. However, passive voice can be useful when the action is more important than who or what is performing it, or when you want to emphasize the object of the action.