Copyright is a form of protection grounded in the U.S. Constitution and granted by law for original works of authorship fixed in a tangible medium of expression. Copyright covers both published and unpublished works.

Although copyrights arise automatically upon creation of an original work of authorship, registering the copyrights with the U.S. Copyright Office can greatly enhance their value. Registration provides a public record of ownership. It can even create a presumption of ownership, which is valuable when enforcing the copyrights in litigation. Registered works may be eligible for statutory damages and attorney's fees in successful litigation.

There is no such thing as an “international copyright” that automatically protects an author’s works throughout the entire world. Protection against unauthorized use in a particular country depends on the national laws of that country. Most countries offer protection to non-U.S. works under certain conditions, and these conditions have been greatly simplified by international copyright treaties and conventions. Generally, a U.S. work may be protected in another country if that country has entered into an international agreement with the United States.

You can register the following types of works:

Literary Works: A literary work is a work that explains, describes, or narrates a particular subject, theme, or idea through the use of narrative, descriptive, or explanatory text, rather than dialog or dramatic action. Generally, literary works include Fiction, Non-Fiction, Poetry, Articles, Periodicals.

Performing Arts: Works of the performing arts are works that are intended to be performed for an audience. This category includes a wide variety of creative works, including music, lyrics, sound recordings, scripts, screenplays, choreography, motion pictures, video games, and similar types of works.

Visual Arts: Works of the visual arts include a wide variety of pictorial, graphic, and sculptural works, as well as architectural works. Examples of visual arts works include paintings, sculptures, photographs, and other types of works.

Other Digital Content: The Copyright Act protects a wide variety of works that are used with computers, tablets, smartphones, videogame platforms, and other electronic devices. It also protects works that are used or distributed on the internet, such as websites, blogs, and other online content.

Motion Pictures: Motion Pictures are works that contain a series of related images that are intended to be shown with a projector, digital display, or other device. When the images are shown in successive order, they create an impression of movement that is perceptible to the eye. Examples of motion pictures include movies, television shows, video games, animations, and similar types of works.

Photographs: The Copyright Act protects a wide variety of photographic works. This category includes photographs that are created with a camera and captured in a digital file or other visual medium such as film. Examples include colour photos, black and white photos, and similar types of images.

Copyright does not protect

• Ideas, procedures, methods, systems, processes, concepts, principles, or discoveries
• Works that are not fixed in a tangible form (such as a choreographic work that has not been
• notated or recorded or an improvisational speech that has not been written down)
• Titles, names, short phrases, and slogans
• Familiar symbols or designs
• Mere variations of typographic ornamentation, lettering, or coloring
• Mere listings of ingredients or contents

The term of copyright for a particular work depends on several factors, including whether it has been published, and, if so, the date of first publication. As a general rule, for works created after January 1, 1978, copyright protection lasts for the life of the author plus an additional 70 years. For an anonymous work, a pseudonymous work, or a work made for hire, the copyright endures for a term of 95 years from the year of its first publication or a term of 120 years from the year of its creation, whichever expires first.

The time the Copyright Office requires to process an application varies, depending on the number of applications the Office is receiving and clearing at the time of submission and the extent of questions associated with the application. The current processing time is 6-10 months.

Reference:
https://www.copyright.gov/help/faq/
http://www.jaburgwilk.com/news-publications/benefits-of-copyright-registration
https://www.copyright.gov/help/faq/faq-general.html