For the ultimate traction, chains on all 4 tires would be optimum . However in reality – most people use chains only on two tires.
Two wheel drive vehicles would only use chains on the drive axle. If you have rear wheel drive, the chains would go on the rear tires. Front wheel drive – chains on the front only.
For four wheel drives, chains normally go on the rear axle. Some four wheel drive vehicles require chains on all tires to prevent drive-train damage. In extreme off-road conditions, chains should be used on all 4 tires.
Each vehicle is unique. Therefore, for a definitive answer, look in your owners manual under snow chains or tire chains. The manufacturer will recommend placement for your vehicle.