Update change-password-or-email.mdx

Clarify that billing & notification systems can have a separate email address

Author: simon-says

src/content/docs/fundamentals/user-profiles/change-password-or-email.mdx

@@ -25,6 +25,11 @@ To change the email address associated with your Cloudflare account:
 5. Enter your current password.
 6. Select **Save**.
 
+:::caution[Billing email & notification email addresses must be updated separately]
+
+The process above will update your user profile email, but it is also possible you have specified separate emails to receive [billing invoices](billing/invoices/#enable-email-invoices-from-cloudflare) and other types of [notifications](/notifications/get-started/#edit-a-notification). You will need to update those as well if you want to receive those emails to your new address.
+:::
+
 ## Change password
 
 :::note