The original authorship appearing on a website may be protected by copyright. This includes writings, artwork, photographs, and other forms of authorship protected by copyright.
Registration is voluntary. Copyright exists from the moment the work is created. You will have to register, however, if you wish to bring a lawsuit for infringement of a U.S. work. It's a good idea to register your website with the U.S. Copyright Office.
Procedures for registering the contents of a website may be found in Circular 66, Copyright Registration for Online Works, linked below.
619-881-2305. This response to your question is general in nature, as not all the facts are known. Please consult an experienced attorney to review all your facts to receive specific advice for your matter. Mr. Paul's response does not create an attorney/client relationship.
If you want to protect your website properly, YES you have to register it. However, you do not have to fill out ANY paperwork at all. It can all be done online at www.copyright.gov . However, you would be foolish to do that yourself since you obviously are a novice (your question tells us that.) See a copyright attorney. The initial consultation, if you ask, is FREE so there is absolutely no benefit to delay, and there is lots of damage that can occur if you delay.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
Any creative work that it important to you should be registered with the copyright office because you will need the registration to enforce the copyright. Unfortunately, it is a common situation for a person to have an infringement come up and be unable to do anything about it for a while because they are waiting for the copyright registration. You can get an expedited registration within a couple of weeks, but it will cost you about $1000.
One big question will be who actually owns the copyright. If you built the website, that it fine. If not, the person who built the website will be the copyright owner unless they assigned it to you. It would be a good idea to seek out a copyright attorney in your area. Copyright registration applications are not very difficult, but it helps to have someone walk you through one or two before trying it on your own.
This is not legal advice. Even if it were, fee legal advice is worth what you pay for it. The facts of every case are different and should be addressed by a competent attorney who has all of the facts.