1. The voice of the verb refers to a basic relationship between the verb and its subject. There are 2 voices: active and passive.
LA VOZOZ

2. La Voz Activa
A sentence is said to be the active voice when the subject is the performer of the verb.
i.e. The teacher writes the exam.
La maestra escribe el examen.
Subject: performs the action of verb
Verb: action
Direct Object: receiver of action

3. La Voz Pasiva
A sentence is said to be in the passive voice when the subject is the receiver of the action.
The exam is written by the teacher.
El examen es escrito por la maestra.
Subject: having the action of the verb performed upon it
Verb: action
Agent: performer of the action; introduced by “por”

4. La Voz
In English, the passive voice is expressed by “to be” conjugated in the appropriate tense + past participle of the main verb.
The meaning of a passive sentence and an active sentence are the same.
In Spanish, the passive voice is formed with a tense of ser and a past participle.
Agent expressed by por if the action is physical and by de if mental
Ser should be in the same tense as the verb in its corresponding active sentence.
Past participle agrees in gender and number with subject.
LA VOZ ACTIVA: El viento destruye la casa.
LA VOZ PASIVA: La casa es destruida por el viento.