My first piece of advice as your editor is to protect your work. You may have heard that your work is automatically protected when you create it, or that mailing it to yourself will protect you. When I first started out, I used these methods, but I learned that they are not the best forms for securing ownership. The only true way to fully protect yourself is to register your work with the United States Copyright Office, Library of Congress (link below). You might also want to take the time to read the two articles.
SCREENPLAY WRITERS: Registering your script with the Writers Guild of America (West or East) is good, but you should also obtain a Copyright for your work. Registering it with WGA is NOT a Copyright.
Copyright Office: https://copyright.gov/
“Why Register When Protection is Automatic”:
“What Automatic Copyright Laws Do and Do Not Protect”: