Roblox allows all users to change their Roblox account's display name in the account settings without spending a dime. Here's how to do it.

Reasons to change your birthday or age on your Roblox account In order to protect the safety and privacy of its users, Roblox set age restrictions and minimum age limits.

Change Roblox username or Roblox display name When you initially sign up to play Roblox, you must give your Roblox account a Roblox username. Other players will see your Roblox name in game.