The passive voice is a change from subject-verb-object.
It involves moving the object to the start of the sentence.
To make the passive voice, you need to use be + past participle
(note: ‘be’ will change depending on the tense you want; the past participle is always the same)
Example of Passive Voice
The cat was eaten by the dog.
The company was started.
The buildings were painted.
Adding details, time phrases, and sub-clauses
Like SVO, the sentence can be improved by adding more information:
Last year, whilst I was still at school, this company was started by my friend from home.
During the bleak winter of 2008, whilst the city was in the middle of a crime-wave, the buildings were painted so that people might feel happier.