All participating teams except the host.
Including the champions of the last World Cup, all need to qualify for the World Cup in the continent to which their countries belong.
In order to advance to the World Cup finals.
The former defending champion can advance directly to the next World Cup.
However, from the 2002 World Cup in Korea and Japan, that is, from the 2006 World Cup in Germany, the defending champion also needs to start from the qualifiers.