Use Passive Voice when the ACTION is more important than WHO does it, or when we don't know/care who does it. Structure: BE (am/is/are/was/were) + PAST PARTICIPLE. The object becomes the subject.
Practice tip: Ask: Is the action more important than who does it? Do we know/care who did it? If NO, use passive! Active: subject DOES action. Passive: subject RECEIVES action.