What is the difference between verbs in active and passive voice?

Active sentences are subject + verb + object. The show the doer (subject ) of the verb.

eg The dog chased the cat.

Passive sentences are not s + v+ o.

eg The cat was chased. (past simple passive)

Passive sentences have the verb form - be+past participle eg was chased

Another example The cake has been eaten. (present perfect passive).

If you want to show who did the action in a passive sentence then add - by+noun or noun phrase.

eg The cat was chased by the dog.