To change your email address just head over to the Account section by selecting the gear icon at the top right.
After selecting the gear icon, select "Update User Information". If changing your email address all communication will be sent to the updated email address.
You can then change your password and select Update.
To change your password just select the box "Change your password" shown in the example below. Checking it will then allow you to update your password. Please note you will need to know your existing password. If you can't remember you will need to Reset Your Password.