To get or change a Roblox Display Name, you should first log in to your Account Info page under Settings, then select the edit button next to the Display Name entry above your Username.

One of the most sought features in Roblox is the ability to change the display name. As of now, players get to choose a username while creating their Roblox account.

To reset Roblox without losing your settings, you need to Clear Roblox Registry entries, Reset Roblox App Data & Clear Roblox Cache.