There are two ways to express an action of a subject in relation to its object

Voice: The voice of a verb tells whether the subject of the sentence performs or receives the action.
Active voice: In active voice, the subject performs the action expressed by the verb.
Active Voice = Doer/Actor (subject) + Verb in Active Voice + Object of Action
Example : god loves all man.

Passive voice: In passive voice, the subject receives the action expressed by the verb.
Passive Voice = Object of Action + verb in passive voice (form of "to be" + past participle) + by actor (optional)
Example : All men are loved by God.

Active And passive Voice: Tense-wise Rules

1. An Active sentence in the simple present tense has the following structure:
Subject + first form of the verb + object
Example:

2.A passive sentence in the simple present tense has the following structure:
Object of the active sentence + is/am/are + past participle form of the verb + by + subject of the active sentence

Examples:

Changing an assertive sentence into the passive

Active: I write a letter.
Passive: A letter is written by me.
Active: I help you.
Passive: You are helped by me.
Active: I love my parents.
Passive: My parents are loved by me.
Active: We love our country.
Passive: Our country is loved by us.

Changing a negative sentence into the passive

Active: I do not write a letter.
Passive: A letter is not written by me.
Active: I do not abuse my servants.
Passive: My servants are not abused by me.
Active: I do not write novels.
Passive: Novels are not written by me.
Active: He does not tease her.
Passive: She is not teased by him.

Changing an interrogative sentence into the passive
Structure: Is/are/am + object of the active verb + past participle form of the verb + by + subject of the passive

Active: Do you write a letter?
Passive: Is a letter written by you?
Active: Do you write stories?
Passive: Are stories written by you?
Active: Does she make candles?
Passive: Are candles made by her?

Active: Who does not obey you?
Passive: By whom are you not obeyed?
Active: Which newspaper do you read?
Passive: Which newspaper is read by you?
Active: Does she do her duty?
Passive: Is her duty done by her?

Notes:
The object of the active verb becomes the subject of the passive verb. Therefore, sentences which do not have an object cannot be changed into the passive. The following sentences, for instance, cannot be changed into the passive because they do not have objects.
The old man sat in a corner.
The child sleeps.
The wind blows.
The dog barks.
The fire burns.
He laughed aloud.

Note: The following tenses cannot be changed into passive voice.

1. Present perfect continuous tense
2. Past perfect continuous tense
3. Future continuous tense
4. Future perfect continuous tense
5. Sentence having Intransitive verbs

Intransitive verb cannot be changed into passive voice
The sentences having intransitive verbs (belonging to any tense) cannot be changed into passive voice. The reason is that there is not any object in such sentences and without object of sentence passive voice is not possible.
A sentence can be changed into passive voice if it has subject and object. Sometimes subject may not be written in passive voice but it does not mean that it has no subject. Such sentences have subject but the subject is so common or familiar or known that if even it is not written in passive voice, it gives full meaning.

For example: Cloth is sold in yards.

Transforming Passive Sentences into Active Sentences

You can transform passive voice to active voice by making the agent perform the verb.

The following
Steps show how to transform a sentence.
Examples: The ice cream cones (receiver) were eaten (verb) by the children(agent)

Step Number One:
Make the agent in the by phrase the subject of the active sentence. Eliminate the word by if necessary
Passive: The ice cream cones were eaten by the children
Active: The children

Step Number Two:
Change the verb from a“to be” form to the appropriate active tense
Passive: The ice cream cones were eaten by the children.
Active: The children ate

Step Number Three:
Make the subject of the passive sentence the receiver of the active sentence
Passive: The ice cream cones were eaten by the children.
Active: The children ate the ice cream

Transforming Active Sentences into Passive Sentences

You can change active voice sentences into passive voice by reversing the steps listed above.

Make the receiver of the active sentence the subject of the passive voice sentence.

Transform the verb into a form of to be plus the past participle of the main verb.

Put the subject/agent of the active sentence into a by phrase or omit it.

Change of Voice Questions from Previous Year Exams

Change of Voice Video Lecture