"We have to shape the World Cup of the 21st Century... football is more than Europe and South America," Infantino told reporters.
With the new format, "many more countries will have the chance to dream."
The World Cup finals currently offer places for 32 teams, but FIFA has allowed an extra 16 teams to play in the 2026 World Cup.
The decision has come in for criticism, with many people believing that allowing more nations to compete will ultimately reduce the quality of the competition.