How do I wire a 220 two wire connection from a water heater to the circuit breaker?

First, you need a 2 pole breaker in the panel to supply your circuit. The current rating depends on the size of the water heater. If you are using a 4500 watt water heater (common 40 or 50 gallon unit) it will require a 30 amp 2 pole breaker. Run 10 gauge cable to your water heater and connect the two hot conductors to the supply wires in the WH and the ground conductor to the ground screw on the WH. If your local jurisdiction requires conduit or armored cable, you will have to do accordingly. Also make certain that you fasten your cable correctly.

First, you need a 2 pole breaker in the panel to supply your circuit. The current rating depends on the size of the water heater. If you are using a 4500 watt water heater (common 40 or 50 gallon unit) it will require a 30 amp 2 pole breaker. Run 10 gauge cable to your water heater and connect the two hot conductors to the supply wires in the WH and the ground conductor to the ground screw on the WH. If your local jurisdiction requires conduit or armored cable, you will have to do accordingly. Also make certain that you fasten your cable correctly.

Does it not require the connection of the common wire (white)?

The white wire becomes the second hot leg. There is no neutral. Only the ground wire goes to the ground buss. On a 240 volt heating circuit that is standard. Look at the way other 2 pole breakers in your panel are wired. Chances are you will see that on another breaker. Dryers and ranges are NOT wired this way. They require a neutral.

To add: The white conductor must be phased black (or any color but gray, or green) at the water heater and service panel.

If you are not comfortable working in the panel, or on any electrical, then find someone who is!

You should pull a #10 for a ground WITH your supply wires, a #12 ground for a 20 amp circuit. Then depending on local code, you may need a #6 from the cold water in to the panel ground.

Then depending on local code, you may need a #6 from the cold water in to the panel ground.Just for clarity, this would have nothing to do with the wiring of the water heater.

Then, I suppose, don't worry about the #6, not Important for this?