If you change your email address, then the new email address will be used when you log into the system from then on. The password will be the same.
You can change your personal contact information on the Your Sponsor Info page. To get there, click on the My Account tab which will bring up your account. Click on your name (link) which will take you to Your Sponsor Info page. Click on the “Edit/Update” link. Make your information changes. Click on the Save Changes button at the bottom of the page to save your changes.