Hello, I'm using craftbukkit-1.17.1 from official site and I don't really understand how to use HEX chat colors. Can you help me please?
What "official" site are you referring to? Anyway, I believe hex is §x§r§r§g§g§b§b, but you will be unable to use it without a plugin because the color char (section sign) cannot be typed in Minecraft.