These days, notices are not required to get a copyright. (Neither is registration.)
However, it is still useful to put a copyright notice on your work. For one thing, it establishes a fixed date and name of copyright holder — it’s a form of metadata that most people recognize and understand. For another reason, it also communicates to the reader, and anyone who might be interested in re-using your work, that the author is someone who cares about their copyright.
The standard form of copyright notice is:
(c) YEAR, Name of Author
Do I need to add “All rights reserved”?
You don’t need to include the language “All rights reserved”. This was language that was part of copyright notices over a hundred years ago, and it does not have any particular legal meaning. Some people apply it out of convention, but it’s not necessary, and it can actually be confusing if, for instance, someone is also applying a Creative Commons license.
Can I apply a Creative Commons license AND a copyright notice?
Yes! It’s easy. Just add your copyright notice, and follow it with a Creative Commons license. The notice tells people the work is copyrighted. The CC license tells them how they can use this copyrighted work.