I need electric wiring diagram for 1997 Champion Mobil Home with 3 bedroom and two baths. All appliances are gas including water heater, we would like to put in an electric water heater, but don't know if there is 220 wiring.

Power is supplied to your home by 2 120 volt supply lines, there is no 240 supply. You make a 240 volt circuit from 2 120 volt circuits and a double breaker. What is the amp rating of your panel, it's on the box cover?

If it's a 1997 home the feed is definitely 120/240V.
You will have the 240V you need.

Also, some mobile homes do provide diagrams, but most do not. It is not typical for builders to leave drawings of the wiring with the end user.

For stick built homes it is almost unheard of.