Fortnite: Battle Royale added the ability for players on multiple systems to play together a while ago, but people are still having trouble getting cross-play to work. Using your standard PSN, Xbox Live, or Nintendo Online account isn’t enough.
You’ll also need to have an Epic Games Account associated with your other accounts to get crossplay to work. Once you have an account and are logged into it on Epic’s website, you need to hover over your username in the top right corner and click the “Account” option.
A new menu should open with a sidebar on the left side of the screen. Click on the fifth option down called “Connected Accounts,” which will bring up another new menu. Once you’re here, press the “Connect” button on any game accounts you want to link your account to. This includes Xbox, Nintendo Switch, PS4, and more. Once you’ve done this, you should boot up Fortnite on any platform you want to use.
To play with friends on different platforms, however, there are some extra steps you need to complete. In Fortnite: Battle Royale on console and iOS, open up the options menu in the top right of the screen and select the “Epic Friends” option from the menu. Here, the game will ask you to enter a player’s Epic Games account username—not their PSN or Xbox Live account name. After following all of these steps, you’ll be able to “Add Epic Friend” to your party—and once they’ve accepted the invitation (or you accept their invite through the “Epic Friends” menu), you should now be able to use “Party Finder” to add them to your group and let the cross-play fun begin.