To change the default gamemode for all players, you'll need to use the LEET App. Once you are logged into the LEET app, go the Settings
section of the app. There you will see an option called Gamemode
. Below the gamemode it will say the default gamemode type for everyone. When I tap the gamemode option, then it will display four gamemode types, which are the following:
Click the default gamemode you want to have on your server. If you just want to change your own gamemode, you can use '/gamemode' in-game.