In creative mode the player(s) can get almost any block in the game and the player(s) can't die ( unless they are below y=-64 or someone types /kill). In creative mode the player(s) can fly and build and destroy anything they want. The player(s) are able to (if cheats are enabled) change from survival to creative by typing in a command.
If the player(s) is in creative mode there are seven blocks that they can't get like the Barrier block, Command block, Minecraft with a Command block, Farmland, Firework Rocket, Huge Mushroom block, Monster spawner, Grass path, Structure block, Structure void, and the Dragon egg. The Ender Dragon will still attack the player(s) even if the player(s) is in creative mode.