What is "Copyright" and why do you need a copyright license agreement

When do we need a copyright license agreement?

You need a copyright license agreement when you have an original piece of work (idea, music, written text, etc.) and you want to prevent other people from using it without restrictions. By obtaining copyright, you receive the exclusive rights to this original piece of work. Normally, it does not last forever and at some point of time, other people will be allowed to use it without your permission. But for the time, for which it lasts, you can use it exclusively in the way you want. Most people use it for profit but other uses are also feasible. 
Most people are concerned about what clauses to include in their copyright license agreement

Obviously, you cannot copyright everything. You cannot copyright any given word you want for your own exclusive use. For example, you cannot copyright words like “love” or “letter” and many others commonly used words in the everyday speech. However, you can register a brand name and if you have the copyright for it, other companies cannot use it without your permission. Well, actually they can use it but you can hold them liable for illegal use of your property (as copyright is property like any other kind of property). Imagine if someone used your house without your permission – it is the very same situation here. Most companies are wise enough not to do that and the ones, which breach copyright, risk serious fines.