What is a Patent?  
A patent for an invention is granted to the inventor, giving the inventor the right for a limited period to stop others from making, using or selling the invention without the permission of the inventor. When a patent is granted, the invention becomes the property of the inventor, which - like any other form of property or business asset - can be bought, sold, rented or hired. Patents are territorial rights.  

What kinds of things do patents cover?
Patents are generally intended to cover products or processes that possess or contain new functional or technical aspects; patents are therefore concerned with, for example, how things work, what they do, how they do it, what they are made of or how they are made.The vast majority of patents are for incremental improvements in known technology; it has been said that innovation is evolution rather than revolution.    

Are there any special conditions that an invention must fulfill?
To be patentable your invention must:
Be new: The invention must never have been made public in any way, anywhere in the world, before the date on which an application for a patent is filed.
Involve an inventive step An invention involves an inventive step if, when compared with what is already known, it would not be obvious to someone with a good knowledge and experience of the subject.
Be capable of industrial application: An invention must be capable of being made or used in some kind of industry. This means that the invention must take the practical form of an apparatus or device, a product such as some new material or substance or an industrial process or method of operation.

"Industry" is meant in its broadest sense as anything distinct from purely intellectual or aesthetic activity. It does not necessarily imply the use of a machine or the manufacture of an article. Agriculture is included.

Articles or processes alleged to operate in a manner clearly contrary to well-established physical laws, such as perpetual motion machines, are regarded as not having industrial application.