Oil light goes on constantly - like within 24 hours of adding oil. There’s no sign of leaks, no blue smoke, nothing. Dipstick says oil needed. ???
If your oil light is on when oil is at the full mark on the dipstick you need to get it to a mechanic ASAP, preferably towed. The lack of blue smoke is that the catalytic converter is cleaning up the exhaust.
You need to add oil until it is at the full mark on the dipstick. Check your oil daily. Please tell us how many miles you drove when it needs another quart. Your car could be leaking oil or burning oil, but the miles per quart is needed information.