“Can we run our car with water and gas?” The engine runs on gasoline, a tiny amount of water can be sprayed in to inhibit knocking and allow higher compression for more power, but it doesn’t improve fuel economy. Too much water or accumulation of minerals from the water will definitely damage the engine. An interesting variation under development is a “6 cycle” engine, with an extra power stroke from injected water turning to steam that both cools the engine and improves efficiency. It requires a large tank of distilled water. It isn’t on the market yet.

“Can anybody tell me is the HHO Gas is real working or is another scam”
Both. Water can be electrolyzed to produce a flammable mixture of 2 parts H2 and 1 part O2, and that will indeed burn in an internal combustion engine. It is still an open question whether producing it onboard can actually produce any improvement in fuel economy at all, considering the power it uses. The minor scam is in the wildly exaggerated claims of improved fuel economy by those trying to sell these devices or plans for making them. Dennis Lee, currently promoting “HHO” under a pseudonym, once pled guilty to fraud in Washington and California involving a different free energy scam.

The major scam is from con artists pretending you can run your car on nothing but water, and using that spiel to sell worthless investments and “dealerships”. Stanley Meyers was convicted of fraud over this one, and others have copied that scam.