Automatic field

When you click in an property, for example:
https://jubenial.com/directorio/apartamento-de-lujo-calle-infanta-mercedes/

You will see a form with 3 fields if you are not registered but if you are registered you will see just 1 field. I want to hide the field of “Email” (when you are a registered user). I want to hide it but I want the information arrive to Make. If you are a registered user it is logic that the Email is your email. Do you understand me?

The idea is to obtain the email of the user without having to add the field.

The page I need help with: [log in to see the link]