Transitive verbs requires an object that will be acted upon, while Intransitive does not.
(私が) ボールを 落とす
I drop the ball
ボールが 落ちる
The ball drops (on its own)
Basically, with transitive verb, subject will do something to an object, while in Intransitive, subject does something on its own.
One thing that may confuse learners is passive and causative, which transform the verb from transitive to intransitive and vice versa. The difference is, there is a hidden subject/doer.
