Which password for iOS update?

There's a software update (iOS 7.1.1) for my iPad and the latter tells me "Enter your passcode". I had assumed this would be my iTunes password but unless I'm getting it wrong this does not work.
Could someone pse advise?
Thanks in advance.
M

It's your local passcode for the device, downloading the iOS update requires your Apple ID and password which is different..

Of course and how very stupid of me!
Thanks for putting me right.
BTW, I'm using my wife's old iPad because she changed to an iPad mini. I've just realised that in "Settings" > "About", both iPad's are quoted as (for example) Mary Smith's iPad. Will it mess things up if I change mine to (for example) John Smith's iPad? The Passcodes are different for the two iPads but we both use the same iTunes account and password.
Thanks in advance once again.
M

That name is just a string that isn't tied to anything in particular. If you plug both the devices to the computer at the same time, it would be nice to have it say "His iPad" and "Her iPad" as opposed to both belonging to His or Her. But again, doesn't make anything...

Thanks very much for the further explanation - all is now clear.
M