er
you don't
the current rating is the maximum it will supply
your circuit will take what it needs
if your circuit needs 2 amps
a) is it an Arduino?!?!?
b) you need to be able to supply 2A so a 10A supply will be fine
Does 7805 will control 12v 10amp supply as per my arduino board requirement?
everywhere i found that, 7805 can controll 24v to 5v, but i didnt find anything about current(amp)
does 7805 will pass 10 amp to arduino?
No, it will not "pass" 10 amps. If you look a the datasheet, you'll see the maximum amount of current a 7805 can supply is going to much less than 10 amps. Furthermore, I don't think you understand the concept that amps aren't "pushed", they are "pulled". In other words, your 10 amp supply isn't sending 10 amps, it's sending UP TO 10 amps. How much it actually supplies, depends on the load. If I told you I could sell you UP TO 10 chickens, that doesn't mean you have to buy all 10 of them. You can buy 2 of them if that is all you needed.
The 10 amps will not be passed on. The arduino will draw the same 200mA-300mA or so that it always has (depending on your loads).
Connect the 5V/Gnd from the 7805 to 5V and Gnd on the Arduino power header.
Put a diode (1N4002 type) from 5V (cathode) to Vin (anode) so the onboard regulator is not being driven in reverse and potentially damaged.
See page 10-11