I need to make the numbers appear and disappear in the same way, but when I hit an NPC
I understand that I have to do TweenService, or what? I have a billboard gui in which I pass the text during the hit and then delete it. Maybe there are some gadayas or videos on how to do this?
You can use a part with a BillboardGui for the damage text. Make the part Non-Anchored and CanCollide false.
To make the part move will can apply a velocity upwards during the first 0.3 seconds of the hit and then apply a random velocity to a random direction, then wait a few seconds and destroy the part.