Is this correct?

She passed on three years ago,

meaning (passed away)

I think I've head them using it in movies..

Thanks in advance!
Many people just cannot bring themselves to say "die". Another expression is 'pass over'.
Yeah, I feel the same way, Clive.

But for some reason, "Her passing" seems okay, while "She passed" is a bit odd.
Teachers: We supply a list of EFL job vacancies
Yes, passed on can mean passed away.
 Philip's reply was promoted to an answer.

I've started hearing people say simply

She passed three years ago

which seems a bit cringe-worthy.

Students: We have free audio pronunciation exercises.
 BarbaraPA's reply was promoted to an answer.