A basic question, is it possible to create codes for the server as if it were a possible gamemode or can you just add codes to the server via plugins?

I'm not sure what you mean by "create codes" and "add codes", could you explain a bit more?

Wulf, what I mean is ... if I wanted to add something to the game, you know? For example ... a system of vip that indicates in the chat who is vip and who is not, this would have to be done through code, right? How would I do that?

Yes, if you don't see something natively in the game, then it would have to be done via code in a plugin. For chat tags, Better Chat would handle that.

Entendido, obrigado!