In Fortnite, you can use map codes via the lobby screen. Open the game and once you find yourself in the game lobby, click on the 'Search' icon that appears on the top left side of the game screen.

In Fortnite, you can use map codes via the lobby screen. Open the game and once you find yourself in the game lobby, click on the 'Search' icon that appears on the top left side of the game screen.