Indicates Ownership
The use of the copyright symbol © (circled "C") or "Copr" appearing on your creative work indicates a claim of ownership.
A circled "P" is used for sound recordings. The use of these symbols should include the year of first publication and the name of the owner.
Registration is not required for copyright or to use the copyright symbol.
You may complete an electronic registration of your copyright, as a matter of public record, but it is not required in order to claim copyright or to place a copyright symbol on your work.
Registration does not require an examination of your "work" or a confirmation of "originality".
The government acknowledges your claim and provides you with a certificate of your registration.
Most countries are signatories to international treaties that recognize the copyrights of member nation citizens.
In most instances, even if your "work" was first published in any of these countries - despite not being a citizen of any of them - you would still receive copyright.
Time Period
Copyrights are valid for a limited period of time. The length of time is usually for the life of the author plus a number of years after his or her death.
In the United States, the time period is 70 years after the author's death. In some countries, the time period is 50 years after death.
These terms differ depending on a number of factors such as whether a company owns the copyright, whether the work was published or unpublished at the time of the author's death, if the author was unknown, if there were joint authors, or if the "work" is a movie, literary expression, music or art.
Moral Rights
The author of a creative work may sell or transfer their ownership of a copyright. However, they would retain a "moral right" to the property.
This means the "work" cannot be altered or used in a manner that would bring disrepute to the author even though they no longer own the work.
You cannot sell or transfer your moral rights but you may waive them. Moral rights usually exist for the same period of time as the copyright.