How do you contact someone on Facebook if you are signed in or ask them to contact you?

search for their name and once you are sure you found the person you are looking for click the "add as friend" button, you can also send that person a message. The next time that person signs in they will be notified of your "friend request" and will be given the option of either accepting or ignoring your friend request. Once they have accepted it you will be free to communicate with them.