how do i change my billing address

You received 'notice' from where ? If an email you are sure that it's a genuine email from iTunes, and not a phishing email :

Phishing and similar emails : Phishing & Other Suspicious Emails

Genuine iTunes emails : Identifying legitimate emails from the iTunes Store - Apple Support

To view the billing address on your account log into it e.g. Account > View My Account menu option on your computer's iTunes, or http://appleid.apple.com

Follow the instructions in this support article for the type of device or computer that you are using to change the info: Change or remove your Apple ID payment information - Apple Support

Cheers,

GB

I received notice that my billing address has changed.. what is the new billing address?

I do not intend to change or input a new address... only confirm what address is now current