There is no single worldwide trademark that covers all countries. Trademark rights are territorial; each registration covers only the country or region where it was granted.
Coverage depends entirely on where applications are filed and accepted. Through the Madrid System, over 130 countries can be designated in a single international application. An EU trademark covers all 27 EU member states through one EUIPO filing. Any country not covered by these systems requires a direct national application.
The number of countries a brand's trademarks cover depends on how many jurisdictions the owner has actively registered in, not on any inherent property of the trademark itself.