Passive voice

The English Grammar Review found in the book version of Merriam-Webster's Advanced Learner's English Dictionary includes the following information about passive and active verb forms:

In a sentence with an action verb (rather than a linking verb) and a direct object, two features tell us who or what is doing the action, and who or what is receiving the action. One feature is word order. The normal word order in English is subject → verb → object.

             The police arrested his wife.

 The second feature is the form of the verb. The ordinary form of the verb expresses the active voice; this means that the subject is the one doing the action expressed by the verb. If a verb is instead in the passive voice, the subject becomes the person or thing that is acted on or affected by the action.

            His wife was arrested by the police.

Here, the original object (“his wife”) has become the subject, and the original subject (“the police”) is preceded by “by.”

Editor Neil Serven provides some other examples: 

Take this sentence:

The car was washed by George.

Even though “the car” is receiving the action, it has become the subject of the sentence. "George" becomes the object of the preposition "by."

If you were to introduce another pronoun, the sentence should read:

The car was washed by George and me.

Here's another example:

Chapter 3 is not well written by Meg.

The subject is “Chapter 3,” passively receiving the action of the verb (“write”). "Meg" is the object of the preposition "by." 

In this example:

Chapter 3 is not well written by Meg. 

Meg is the subject, the doer of the action (writing). 

Chapter 3 is the object, the receiver of the action. 

Write is the verb, shown in its past participle form (written), used in the passive with a form of be (is) as a helping verb.