The iPhone Xs MAX can use a 12w charger.
All models after the iPhone 8 support fast charging, you can use Apple's own 12w, 18w, 45w, 60w, 85w charging head (the back three are Mac) USBc lightning interface data cable, the first 30 minutes can be filled with half of the charge.
Can charge charge speed will be fast but the fastest fast charge is 61W charger 12W is not the best