how to download free apps on iphone without credit card

Yes, this is how Apple verifies your account and Apple ID if you do make a purchase they can charge for. There is an option to create an Apple ID without a credit card, but that has to be done a special way in the beginning. Once you create the Apple ID, you cannot go back and change it.

Yes, either that or you redeem an iTunes gift card if you want to use your existing Apple ID. Otherwise, you create a new ID & follow the instructions here:

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