Unfortunately, we do not have the option for the panelists to choose their own passwords at the moment. What you could do is to go to the login page and request a password reset. You will then receive a random generated password to your registered email address.
You also need to contact us if you need to change your registered email (which is also your username). This is because the username (email) is controlling where the payment should go - and therefore it would be a security threat to let the users change this themselves.
Please let us know by contacting our Support Team, if you wish to change your email address, we can do it for you.