There are no built-in cheats in Ravage. Ravage is designed to be difficult and using cheats will remove a lot of the fun. But if you really wants some cheats in single player, then you can add them using add-ons and mods.
Kronzky's Support Call
Download link and information page: http://www.kronzky.info/addons/supportcall/index.htm
Kronzky is a Bohemia contractor and his Support Call add-on has been around for quite a while. The ArmA 3 version works with Ravage. Although not all the functions will be usable (e.g. changing the weather only works for a short time), almost of all them are.
You can spawn vehicles, weapons and ammo (ArmA 3 defaults only) and these will be air-dropped to your current location. You can also detect enemy and friendly troops, which is particularly useful for developers testing their own missions and mods. You can also skip time and launch drones.
Support Call is really best for dropping in weapons and vehicles. It doesn't offer invincibility or any other kind of 'god mode' cheats and is one of the milder cheat options. It's accessed through the main in-game menu - during a game, press Escape and press the "Call for Support" button that has been added to the main menu. The Support Call window will then appear and you have to go back into the game to access it. It does not pause the game whilst you're accessing it.
Trivia: Kronzky was the first person to develop a single player mission for DayZ
Simple Single Player Cheat Menu
Download link and information page: http://www.armaholic.com/page.php?id=28400
SSPCM is a more comprehensive cheat system that allows for very powerful effects. You can use the Virtual Armory to changes clothes, weapons and every aspect of your loadout. There is also access to the Virtual Garage that allows the spawning of most ArmA 3 vehicles. It allows invincibility (for players and vehicles), teleporting (view and map-based), disabling of fatigue, Zeus operations, infinite ammo (current weapon only), bullet tracing, bullet cam, change of alliances (e.g. enemies become friendly) and you can even instantly respawn in a flying jet. It has a lot of features.
The main caveat is that it completely ruins the game. There can also be problems when loading saved games - the game will continue, but SSPCM may not work.
Access it through the map screen (even if you don't have a map) and pressing the "Load SSPCM" button at the top. A new entry called "Cheats!" will be added to the menu on the left side through which you can access all of its functions.