The Mobile Operations Center (MOC) in Grand Theft Auto Online allows players to modify certain types of vehicles. The following vehicles can be modified in the MOC:
1. Weaponized Vehicles: Weaponized vehicles such as the Oppressor, the APC, and the Half-track can be modified in the MOC.
2. Special Vehicles: Special vehicles such as the Ruiner 2000, the Rocket Voltic, and the Blazer Aqua can be modified in the MOC.
3. Personal Vehicles: Personal vehicles such as cars and motorcycles cannot be modified in the MOC. However, players can use the MOC to modify certain weaponized and special vehicles that they own.