Q: How do I find the code for Apps for iPads?

What code are you referring to ? Do you mean the code on the back of iTunes gift card (redeeming a code) ?

There are no codes needed for any free app. Please explain in detail what it is you're trying to do and where you're running into difficulty.

Regards.

Again, it's not clear what "code" you are talking about. Are you talking about your Apple ID name and password? Or are you being asked to enter in a payment method when you try to set up your iTunes Store account?

If you're being asked for a payment method, then you will need a credit card or a prepaid iTunes card (which you redeem per the information King Penguin provided. If you only want the free apps and cannot enter a payment method or do not wish to do so, take a look here:

http://support.apple.com/kb/HT2534

Read the steps carefully as the order in which you follow them is  critical. Note that you can do this only when creating a new Apple ID. You cannot use an existing ID. 

You will of course not be able to get anything other than the free apps without entering in some sort of payment method (credit card, prepaid iTunes card, gift certificate, etc.)

Regards.

Then it's asking you to enter a payment method, though if it's a free app you won't be charged - you can either enter a credit card or an iTunes gift card number (if they are available in your country).

You do have to enter your password, even if the app is a free one. That's the way the App Store works.

If it's asking for a password, it's asking for the password for your Apple ID, the one you used, or created, when you set up your iTunes Store account.