A patent only provides protection within the country in which it is granted. Therefore, an inventor must file for a patent in each country where patent protection is desired. Most countries require that nationals file for a patent in their own country before seeking foreign patent protection.
When an applicant files on the same invention in multiple countries, these applications and the subsequent publications are collectively known as a patent family.
This can be used to conduct patent searches to find out in which countries a company is planning to become active in the future.