In order to show the copyright it is accustomed to use several symbols that are not quite the same.
The ™ or SM symbols are to be used for marks that are claiming the rights to the creation or for marks whose trademark applications are pending. Sometimes these symbols are governed by the state laws so it may be useful to check with the local authorities.
The symbol ® means that the trademark is Federally registered. It should be used only if you have received Federal trademark registration.
The sign © can be used with any copyrighted material, registered or not. Unlike trademarks, copyrights appear as soon as something is created, so you can use this symbol freely for anything you create that is covered by copyright (images, paintings, books, music, etc.)
A lot of work is being done and sold nowadays online. Is your website protected? Since everything is considered to have a copyright as soon as it is created, websites are protected by copyright even if you do not choose to register the copyright, and in this case you can freely use the copyright sign.
Once you produced your creation you can add the TM symbol, and it gives you a level of protection. You can put ™ on anything – it just means that you consider it to be a trademark for your creations. You can use the sign ™ quite freely.
The sign ® is used to indicate that your trademark is registered with the government. Only use the sign “Registered” if you’ve actually registered the trademark formally.