Mutlaa is an area north of Kuwait. The landscape is different there, more rocky and ridgy, the sand also feels different. Some of the areas are now being turned into a residential city called Mutlaa City. There is also a military zone.
The government has marked specific sites for camping, but those are mainly set for larger and long-term camps and require you to register and pay insurance for the government. If you're doing a one nighter with your friends you shouldn't bother doing that, you can just camp anywhere. But be wary of where you are setting camp. Like any wild area in the world, it has its dangers and precautions. It's best that you ask around about safe areas, or invite someone who has camped before in the North. Some people have marked their favourite locations with GPS coordinates and maybe they can share them with you.