No electricity needed.

Dual carbs use the same: about 3 pounds of fuel pressure.

electricity?

Most aftermarket electrical fuels pumps will come with everything you need for install. i.e. wire, mounting bracket, some even come with a fuel filter, and additional directions for wiring it into your oil pressure switch for emergency shutoff.
Assuming you are running a stock Hitachi carb or Webber 32/36, you should not require a pump that puts out more than 4psi. 3 to 3.5psi is probably ideal.

You might need:
1. Additional wire
2. Additional lengths of flexible fuel line
3. In-line fuel regulator
4. A new grounding location

You will obviously need to get or fabricate a plate to cover the hole left from the mech fuel pump.

If you are running some type of dual carb setup or fuel injection; I will leave that to someone else.

If we replace the mechanic fuel pump for an electric one what do we need beside the electric fuel pump? Sorry for the stupid question!!