You can register them with the Copyright Office
According to US Copyright Law, you own a piece of intellectual property once it is completed and fixed in some tangible form (like a demo or a lead sheet). What the Copyright Office provides is not the copyright itself, but a certificate of registration of your copyright. This is a formal document issued directly from the Copyright Office to you that certifies that you are the owner of a work and that they have a record of your ownership on file at the Library of Congress.
Some people prefer to register their works with the US Copyright Office as a way to prove their rights in court if there was ever an infringement of their copyright. Songtrust does not register your works with the Copyright Office. However, you can do this on your own by completing the copyright forms available from the U.S. Copyright Office and including a copy of your work in a tangible medium.
*Please note that the policy on copyright law is different in every territory. Please check your local laws as necessary. We suggest you consult a legal professional to decide whether you should register your works with the Copyright Office. We are not qualified to give legal advice.