Help on ETF

Hello. New to investing. Started a couple months back. 26 years old. I just need to know if investing in ETF is better than investing in shares ? And is it better than mutual funds ? And what is the safest option out of these three ? I have around 5L to invest as of now. For long term and hassle free life. I have a particularly busy schedule in hospital so very less time for the market. Id be thankful if someone could provide a gist of it.