If your Domain-Name is just "parked" and not being hosted, it is normally impossible to use the Email facilities attached to it. However the concept of Email Forwarding changes that. Whilst you cannot send messages using your Domain Address, you can have Email addressed to your Domain forwarded to an existing Email Address of your choice. For example, if you have registered and "parked" a Domain-Name called mybusinessname.co.uk, and you have an existing Email account called someone@my-business-name.co.uk, you can arrange to have all Email addressed to anything@mybusinessname.co.uk to be forwarded to someone@my-business-name.com.