I do not have an email address, can I use my XXX's to register?

I would strongly recommend NOT to. Your account might contain your sensitive information such as your draft Will, which if you register with your Son / Daughter / Wife/ Uncle / That Random Guy Called Tim, then Son / Daughter / Wife/ Uncle / That Random Guy Called Tim could potentially access the information.

It doesn't take long to create another email address, personally, I like Gmail so here's the link if you like to have one.