Codex Coop Games – Ylands

The co-op settings allow game owners to set up three levels of permissions for their games and apply them to their clan, friends, and others.

Mayor: Can place entities. Can easily deconstruct entities placed by other players. Can capture blueprints. Game owner is mayor by default.
Citizen: Can place entities. Can damage and destroy entities. Can't capture blueprints.
Visitor: Can't place entities. Can't damage entities. Can't capture blueprints. Can't modify terrain.

Co-op settings are present in all explore games and sandbox games.

Turn on coop mode in editor

You can turn on coop mode for your game in the editor via
Game -> Game Settings -> Multiplayer -> Co-op game