Active voice means the subject is the agent. Passive voice means something other than the subject is the agent. video
Take the sentence,
The cat ate the mouse.
“cat” is the subject, and it is doing the eating. Therefore, the verb “ate” is in the active voice. In this sentence,
The mouse was eaten by the cat.
“mouse” is the subject, but it is not the agent. Therefore, the verb “was eaten” is in the passive voice.
Greek also has active and passive voices; but in addition, has a middle voice which has various meanings (BBG 25.15). cf. deponent
In Hebrew, the passive voice is conveyed in the nifal and pual stems.