You may want to change your Apple account’s security questions and answers for various reasons (e.g. you forgot the answers). You can change your answers provided when you signed up for your Apple ID. To do this, visit My Apple ID. Then click on the “Manage your account” link to log in to your account. Then select Password and security. You need to answer (and remember) your security questions in order to change your security questions.
However, if you forgot your answers (this may be the reason that you want to change your answers), there is an option for you to reset your security info. To do that click “Send reset security info email to (your email).” After clicking, Apple will send you an email explaining how to reset your Apple ID security questions and answers; simply follow the instructions.