A valve is a piece of metal, plastic, other material, that is in a pipe/line, and provides a "restriction" to flow.
When people say electric valve, it is usuall taken to mean an electric actuator on a valve. An electric actuator uses electricity to move/stroke a valve.
An alternative is to use a pneumatic actuator. In which case, air (or N2, fuel gas, etc.) is used to move/stroke the valve instead of electricity.