The securing of copyright protection is frequently misunderstood. Copyright is secured automatically when a work is created. A work is "created" when it is fixed into a book, tape or electronic medium for the first time. For example, a song can be fixed in sheet music, a digital tape or both.
No publication, registration or other action in the U.S. Copyright Office is required to secure copyright. However, to enforce the copyright and for other practical reasons, it is highly recommended that you to register your copyright with the U.S. Copyright Office.