Copyrights extend broad legal protections to individuals and businesses that create original works of authorship in a fixed and tangible form. What the latter part of that first sentence means is that the work must be written down or recorded in some way. You can't have an improvised speech or impromptu performance protected under copyright.
But say you have written or recorded your work and want it to be copyrighted. What does it even mean to have something copyrighted?
A copyright grants the holder of the copyright the exclusive right to reproduce, publish or sell their protected work. Now, this doesn't mean that the details involved in the original work are protected. Instead, it is the "form of material expression" that is protected under a copyright. Effectively this means that the copyright holder alone can reproduce, distribute or perform the work, as well as derive other works from the copyrighted material.
Getting a copyright can take some time, and there are limits to what can be covered under a copyright. But that is where other forms of intellectual property law can fill in the gaps. Trademarks and patents can help legally protect other concepts that a copyright wouldn't.
Ultimately, copyrights need to be enforced and protected by their holders. A copyright means nothing if the holder doesn't actively use it and hold infringing parties responsible when they use or steal your copyrighted work. Use the legal rights granted to you if you hold a copyright.
Source: FindLaw, "What Is a Copyright?," Accessed Feb. 9, 2017