Some users may not get the popup to create an Epic Games Account name when setting up their account in game. When this happens, you'll get assigned a randomly generated Fall Guys name until you update your account.
Click here to go to the Epic Games Play Support Portal and find out how to update your Display Name for your account.
If you miss your randomly generated Fall Guys name, feel free to use them as inspiration for your new custom username! You can set that in your Epic Account when you sign up, or change your Epic Username if you already have one - but remember you can only do that once every two weeks!