Copyright is the intellectual property right that protects the expression of an idea or information, a ‘work’. It gives the creator of the works the right to control uses of the work, uses like reproduction, adaption and showing it in public. It’s automatic, as soon as the work is recorded in some way, written down, recorded, twittered, then copyright protects that work. It doesn’t have to be artistic, or commercial or substantial, a two sentence note asking your partner to buy milk is automatically protected by copyright. The creator can transfer some or all of these rights to another person, so the creator is not always the ‘rightsholder’.
In order to use a copyright work, or part of a copyright work, then you need the permission of the rightsholder, often given in return for payment. This can be expensive, difficult or even impossible. Sometimes it’s just not possible to track down the rightsholder for a work.