So if you view the wikipedia page on email it is long, and some of it’s sections have their own dedicated pages. There is a lot of information, and links to even more information. All of it related to email. For a new comer this is a daunting sight, and gives the impression that email is complicated.
Much of this information is supplementary however, talking about things that surround email, and not actually central to what email is. If we take out the supplementary information we’re still left with a lot, but this can be broken down, and separated out into the specific parts of email that it applies to, and fundamentally email isn’t very complicated.
At it’s heart email is a way to send a message from one user, on one computer system, to another user on another computer system. It really is that simple, there are lots of details on how to make this concept work, but basically email is like post but for computers instead of towns or cities. One user creates a message on the computer system they are on, and send it to another user, on another computer system, and email is how that message gets from being written to being read.