In most countries copyright is a fundamental right given freely to you for each and every creative work you make. Thus as soon as you take a photograph, write a story, compose music, make a film, etc., the law automatically makes you the owner of the copyright invested in that work. However, if you are an employee the copyright may be owned by your employer if you created an artwork in the course of your employment.
As owner of copyright you have the exclusive right to license your work to others who may wish to use it. Without a license from you other people or organisations are not legally permitted to use your work. In a license you can specify limits on usage including -
the agreed use to which your work is to be restricted (e.g. a book cover),
the date on which your work must cease to be used,
in which countries your work can be used,
how much you want paid (the usage fee) for the requested rights.
These are important and valuable rights and you do not have to be a professional artist to enjoy them.
For example, if you are just a happy snapper and enjoy taking photographs you own the copyright in these photographs. There are organisations who would like the right to use them, and to obtain those rights from you for nothing.
So they will launch a competition, invite you and others to enter and submit your works under terms and conditions that claim your copyright or some other important part of your rights. Such competitions depend on the public not understanding the value of copyright and related rights.
Of course now that you know about copyright you won't enter such competitions, will you? If you would like to know more about copyright and related rights please read our Guide to Rights and Licensing.