I wanted to use uefn with my friends but I couldnt figure out if it was possible…
Only one person can do updates in the UEFN editor. It IS possible to have multiple people inside of the Fortnite game itself when you click “launch session”. Simply invite your friends in-game and make sure they have the correct permissions to edit the map inside the Fortnite game.
To simply answer your question, no you cannot, I believe.
You can do this if you make a team. Every team member has to be over 18. Make sure your project is the team’s project and you can both be in UEFN to develop the game. Don’t work on the same area if possible, but version control manages a lot of it for you.