Can someone help me , i need to draw a house'electrical plan for the first time and i want to know which autocad must i use. Thanks

It could easily be done in plain AutoCAD.  AutoCAD Electrical would, in my opinion, be massive overkill and a waste of money for a project like this.You are basically drawing a floor plan that will show the location of all outlets, wall switches, overhead lights, wall mounted lights, fans and any specialty items like a garbage disposal or a wall mounted heater.  You probably should specifically call out any GFI (ground fault interrupt) outlets.  The only wires shown are those that go from a switch to the light or device that it controls.  You do not need to show each and every wire in the house.

Here is a link to an article that you might find helpful.Understanding a Residential Electrical Planhttp://homedesign.8m.com/articles/

AutoCAD MEP would be probably the best option but any plain AutoCAD or even AutoCAD LT will do.

MEP?  Wouldn't that be overkill as well?  Now, if he were drawing a electrical power substation or a chemical plant maybe MEP would be the way to go but not for a house.