Answer 1

Just add prefix to your nickname

Answer 2

You want to have tag above player or in chat?

Answer 3

So like in chat?

Answer 4

I understand that your game is multiplayer. When you are joining the server, add to your nickname prefix [DEV]. Or create new object with player nickname and message, add prefix and add it to chatbox

Answer 5

So that's it. I won't give you code due to Self Learning, but my tip is to check if you are developer and as I said before add dev tag before your nickname