Apple Custom E-mail
So if I set up a custom e-mail domain people that I e-mail will not know if is from me until they open the message. Am I correct? If so then they many think it spam mail and delete it. Am I correct?
Depends. You have to buy and own the domain first, so will need a domain hosting service account with a hosting company. Apple does not host domains, so you need to do that first before you can use the domain with your Apple mail. You can use your own name (first, last, initials, whatever) when you register and create your own domain. So you could make a domain name that identifies you specifically in the very name.
So keep in mind your going to have to pay monthly or annually for a domain hosting account somewhere and pay the annual domain registrations unless those are bundled into your hosting fees.
Still, if people use contact filtering to block unwanted mails, you’d need to tell people what your new email address is so they can update their contact information for you.