USB-C describes the connector. USB Power Delivery (PD) lets the phone and charger negotiate power. Wattage equals volts × amps, so 9 V × 3 A is 27 W. PPS adjusts voltage and current in finer steps. For peak speed, match the phone’s required profile and use an electronically marked 5 A cable where required.
Proprietary fast charging can require a compatible charger and cable. On multiport chargers, check the power available per port when several devices are plugged in. Heat and battery level can reduce charging speed.
Qi is a wireless charging standard. Magnetic Qi2 aligns the coils, with versions rated for 15 W and 25 W. Check the phone, pad and wall adapter together. MagSafe is Apple’s brand, while Qi2 is an industry standard.