A patent is an exclusive right granted when a person files an application on the Intellectual Property institution of the respective country where the inventor wants to protect their invention or a utility model.
The invention could be a product or a process that generally provides a new way of doing something, or offers a new technical solution to a problem.
The patent owner (inventor) can give a permission or license to other parties to use the invention on mutually agreed terms. If the inventor wishes he/she can sell the patent to someone else, and that person will become the new owner.
Depending on the country where the patent is granted it receives certain amount of years to protect the product or process, but once a patent expires, the protection ends, and the invention enters to public domain; meaning that anyone can commercially use the invention without infringing the patent.
In El Salvador the Patent is granted for 20 years.