When send an email by my wordpress site, who recive the email watch my addres email + through william-paterson.dreamhost.com who is william paterson ? Can I edit example mydomainame.dreamhost.com ?thanks
william-paterson is a name of a server at DreamHost. I believe it's named after William Paterson, the second governor of New Jersey.
You cannot create your own subdomains of dreamhost.com.