A forwarder/alias is just an email address that when an email is sent to it, it forwards to another email. You cannot send email from this address.
A full email would be like any other, you log in to receive email and you can send it like any other.
A mailing list is an email address that is a sendto only. It has a list of email addresses and when you send to the primary address it forwards that message to a whole list of email addresses in the list.