A screenplay is technically copyrighted the moment that you place it in a tangible format, such as saving it to your hard drive or writing it down on paper. However, in order to further protect your screenplay you may wish to register your copyright through the U.S. Copyright Office so that you can sue anyone who might violate your rights. In addition, you may wish to consider taking some extra precautions such as placing a copyright notice on your screenplay before you distribute it to others.
Obtain a copyright registration form from the U.S. Copyright Office or register to complete a form online through the Copyright Office's Website. Online registration has some benefits including a lower filing fee and the ability to upload your screenplay to the Copyright Office rather than mailing a copy.
Complete the registration application form. Under the section of the application that asks what type of work you are registering, select "Literary Work." If the screenplay has multiple authors, you may enter multiple parties in this section of the application and the copyright will be registered as a joint work. Remember that all resulting profits must be split equally with co-authors unless you have an agreement to the contrary.
Upload your screenplay to the Copyright Office's Website through the procedures outlined in their application. Mail your screenplay to the Copyright Office if you decided to use a paper application.
Submit your completed copyright application and the applicable filing fee to the Copyright Office.