The iphone12 fast charge cable is 20 watts.
The full range of iPhone12 supports PD fast charging, the official charger on sale is 20W, but the actual charging speed should be about 20W, iPhone12 also supports MagSafe wireless charging (power up to 15 watts), Qi wireless charging (power up to 7.5 watts), Fast charging up to 50% charge in 30 minutes, using a power adapter of 20 watts or more.
20w power 9v voltage, resulting in a current of 2.22 amps