why do i need my unlock code to reset my iphone password?

I'm trying to help an elderly person who forgot their iCloud.com/apple password. When I try to reset her password going through the normal process of using another apple device (my iphone) to do the reset password all is well until they ask for her phone's prior unlock code. She has not been using the lock phone feature (it's turned off) and she has no unlock code that she knows of. Do all iPhones require you to initally put in an unlock code in order to operate even if they turn the feature off and don't use it OR is it optional to create an unlock code or not? Is there a way to bypass this step? What is the best way for her to reset her password given the circumstance I've outlined.

Unfortunately she is no longer visiting me and not fluent at all about this stuff. Her phone is working fine, mostly I just need to get and app downloaded from the app store for her new car accessories but can't without the apple passworld....Help please