Anything that you put on your website that is your original work is automatically copyrighted. However, that doesn’t stop some people from using your materials without your permission.
What you can do is put a copyright notice on your pages (along with the copyright symbol). You can put your copyright information into a Text Widget at the bottom of your page. Here is a link that will give you more information about this: Copyright Symbol.
You can enter your own copyright symbol into a text box by using the correct keyboard shortcuts:
- If you are using a PC use CTRL+ALT+C
- If you are using a Mac use Option key+g
Another thing you can do is publish your works under a license. Creative commons provides an easy way for you to choose a license for your work. Check out their license generator: Creative Commons.
If you do become aware that someone has copied your original work, you may have legal recourse against them under the DMCA. If you do, you can send someone who copies from you a takedown notice directly.