A patent is a document which describes an invention and creates a legal situation which the patented invention can normally only be exploited (manufactured, used, sold, imported) with the authorization of the owner of the patent. Invention means a solution to a specific problem in the field of technology.
The invention must be ‘new to the public’ ; i.e, it cannot be disclosed in public information (prior art) existing at the time of the priority date (usually the patent application date).
An invective step is not obvious to a person skilled in the art. Sometimes it is finding a way of doing something which people had wanted to do but could not think ‘HOW’
An invention must be industrially applicable it can be produced or used in any kind of industry, an invention regard to well-established law of nature.
Patent protection grants you a monopoly on that invention for 20 years from the patents application date.