Passive voice creates unclear, wordy sentences by using the subject to receive, rather than perform, the action of the sentence. To change a sentence from passive to active voice, the person or thing performing the action should be used as the subject, and the third form of the verb should be used in passive sentences. Sentences with intransitive verbs or those using the perfect continuous tense cannot be changed to the passive voice.

1. Passive voice
Definition: Passive voice produces a sentence in which the
subject receives an action. Passive voice often creates unclear, less direct, wordy
sentences .
Explanation: To change a sentence from passive to active voice, determine who
or what performs the action, and use that person or thing as the subject of the
sentence.
In passive voice sentence ,we use By To With
Sentences having intransitive verbs cannot be converted into passive voice .
Sentences which contain perfect continuous tense cannot change into passive voice.
In passive voice sentences we use only 3rd form of verb
Examples:
1- she plays football.
Football is played by her
2- Amina is watching a movie

2. Present indefinite tense
 Active voice
 Simple:
 Sub+1st form +s/es + obj
 Ali eats pizza.
 Sub+do/does not+1st form+obj
 Passive voice
 Simple:
 Obj + is/are/am+3rd form+ by + sub
 Pizza is eaten by Ali
 Obj+is/are/am+not+3rd form+by+obj
Simple: Simple
Negative: Negative: