I want to know what The P R N D D2 L stand for

on the gears, your know Park Reverse N D

And what is is Od- Over drive and the ELec Power what purpose do all these serve

Usually the L means low or 1st gear and it will hold that gear indefinately to redline
D2 means it will hold 2nd gear indefinately and depending on how the tranny is set up will either start off in first and stick with 2nd or start off in 2nd for use in slippery snowy conditions to get going when you are stuck or to prevent slipping in snow
D is drive and it usually includes overdrive unless it is (depending on vehicle) disengaged
Elec Power not sure what that is but if it is ECT Power than it is a different shift mapping for the tranny to follow to hang on to gears a little longer to give you a sportier experience and more driver oriented control.

Can you go in detail I have no clue about cars?

And yes it is ECt Power and what is over drive and how do you know if it is on or off?

I'm not familiar with the shift pattern on your vehicle, over drive is the highest gear in the transmission, when you put it in drive on the indicator, it is in overdrive, if it doesn't have a button to disengage overdrive then you will have to manually move the shifter to the next gear, it may only have 4 gears one of which is over drive so to get it out of over drive it would have to be placed into 3 probably not a great idea unless you are primarily doing less than 45mph all the time.

ECT Power like I said before should be a button that controls at which points the transmission will shift, it may hold on to a gear a little longer before it shifts, maybe the difference would be like shifting at 500 rpm higher or something like that. it gives you a different driving feel when driving it quickly or in a sporty manner.

ok so whats does Od actually used for?

Just leave the shifter in D for drive if you are going fast enough it will use over drive if you aren't it won't, primarily it is to use a higher gear so the engine will turn slower for the same speed and consume less fuel.

OS stands for OVERDRIVE. Overdrive means that the rear wheels turn faster than the engie RPM's. "D" (Drive) is 3rd gear in most cars (with 4 speed transmissions) which is a 1:1 drive ration. Overdrive is very useful in reducing engine RPM's and therefore, fuel economy. These cars have 4 speed sutomatic transmissions so 4th is simply the highest gear. 1st (L) 2nd (2) D (3rd) OD (4th)

I meant OD, not OS
so I can't type.