Two ways to protect a trademark abroad
With the traditional route, you submit a separate trademark registration application in every country where you want protection. Each filing is its own application.
The Madrid System works differently. You begin with a single application or registration in your home country, and then extend it through WIPO to any other countries you choose. These additional countries are called "designated countries."
Cost considerations
If you plan to protect your mark in several countries, usually five or more, the Madrid System can turn out to be the more economical option.