email and password automatically filled in – how to change?

Hello,
I am using the shopp customer register here: https://jacanagallery.com/fine-art-shop/start-a-registry/

On my screen, even when logged out, the email and password fields are automatically filled in.

Is there a way to change this, so that all the fields are empty until a user fills them in?

Is there also a way to make some fields required and some not?

Thanks!