When people are learning English grammar, they often feel confused by the passive voice. Let’s keep it simple:
Use object + be + past participle + (by subject).
|Object||“Be”||Past participle||(by subject)|
|The bike||was||stolen||by somebody|
To change the tense, change “be”. Everything else stays the same.
|Past simple||His bike||was||stolen||(by somebody)|
|Present continuous||His bike||is being||stolen||(by somebody)|
|Present perfect||His bike||has been||stolen||(by somebody)|
Change these active sentences into passive sentences.