Copyrights are the easiest intellectual property to register. On the other hand, patents and trademarks necessitate expertise that may require the assistance of an intellectual property professional, especially patents. However, trademark registration is a viable option for some to tackle on their own.
Although you need not register your copyrighted works with the US Copyright Office, there are legal advantages to do so. Registration establishes a pubic record of copyright claim. Before a copyright holder may file an infringement suit in court, registration is necessary. It also allows the copyright owner to record the registration with the U.S. Customs Service for protection against importation of infringing copies, e.g. fake or counterfeit copies.
Start at the US Copyright Office website https://www.copyright.gov/:
The current copyright cost is listed, along with directions. There are different forms for various types of works, e.g. literary texts, sound recordings, etc. For example, literary text forms are used to register published or unpublished non-dramatic literary works, excluding periodicals or serial issues. Texts include a wide variety of works: fiction, nonfiction, poetry, textbooks, reference works, directories, catalogs, advertising copy, compilations of information, and computer programs.