In active voice, the subject does the action as stated by the verb and in passive voice, the subject is acted by the verb.
Example:
1_ Simi ate five appples (active voice)
2_ Five apples were eaten by Simi (Passive voice)
Explanation: Clearly, in sentence 1, Simi is the subject that does the action (ate), so active voice.
But in sentence 2, Five apples were eaten (this is the verb that has acted on the subject) by Simi
