Disney gives you a few marked envelopes & paper slips, night or two from end of cruise, showing your prepaid tips with their names to hand them.
If tipping any extra (in that envelope or directly to them) it’s personal preference. I have given extra but it’s not a requirement when daily tips are charged within your cruise. I usually will give more to my cabin attendant than any other. More to my direct table attendants than the supervisor.
On non Disney cruises I’ve only given extra to our cabin attendant. Disney a bit different since we bond with the dinner staff, keeping them for the whole cruise.