I just found this post here about copyrights. Back in the 1980’s I use to publish newsletters. I did have one copy of one of my issues copyrighted, I forget how much it costs back then to do so. It probably costs more nowadays.
Well, there is a cheaper way to copyright it yourself. For one thing don’t forget to date it, and mail a copy to yourself. DON’T OPEN IT! Put it in a safe place, like a safe deposit box. The envelope will have a dated postmark on it as proof when you created it. I’ve done that, and it makes me feel safe knowing it is proof that it’s my creation. Give it a try!