How do I change the billing address on my account?

If you want to change the email address your payment receipts are sent to, you can do that within your account settings. 

Note: You'll need to be an admin user in order to make this change.

Head to Account Settings → Subscription. Once you're on that page scroll down to the Payment section:

From there type in the email address that will be your new billing contact and click Update email.

And you're done! All future receipts will send to that email address going forward.