I think we need to know exactly what you are asking. For example in many Western cultures, a woman will wear an engagement ring on her ring finger. Both men and women may wear wedding rings on their ring fingers. As culture changes these customs may relate to same-sex marriages etc.
Picture of wedding and engagement rings on ring-finger
You might ask, "On which finger is a wedding ring worn?"
You could say, "On which finger is a ring worn?" but the answer would probably be, "On any finger you like!"
Another possibility, "Which finger do you wear your ring on?" (i.e. you specifically)
"Which finger do you wear your engagement ring on?"
I automatically read it as the ring, probably because a ring can be worn on any finger, but the ring is a wedding ring, as we call it in the UK, which must be the most commonly worn ring especially among men. In the UK, wedding rings are worn on the 'ring' finger of the left hand, the fourth digit, but in some European countries (maybe all) it's worn on the right hand.
I think wedding rings for men might be relatively recent otherwise my husband would have had one when we got married over 50 years ago. He wore a family signet ring on that finger. They are traditionally worn on the little finger.