Where did you register the domain name? The reason I ask is because that’s usually the best place to also set up an email address.
If you registered your domain name at GoDaddy, as an example, you would follow the steps outlined in this tutorial to set up an email account using your domain name:
Just about every domain registrar also provides email addresses as an add-on purchase. And they’ll have their own documentation on the steps to set one up.
Hope this helps!