What you need to know about wireless charging...
While wireless charging provides a great convenience and aesthetic, it is important to understand how it works and how it differs from wired charging.
Wireless charging uses an electromagnetic field to transfer energy between the transmitter coil (inside the charger) and the receiver coil (inside your phone). Alternating current (AC) is sent through an inductive coupling to an electrical device (your phone), which generates current within the receiver coils. This current is converted into direct current (DC), which charges the battery of the device.
Wireless charging is great because there's less cable chaos. However, it can also be less efficient (slower charging rate) than wired charging due to the energy that is lost in the transfer of power from the transmitter coils in the charging pad to the receiving coils inside your phone. For example, it is normal for an iPhone X to take 3-3.5 hours to obtain a full charge using a wireless charging pad. iPhone XS Max will take around 5 hours to charge from 0% to a full 100%.
Wireless charging can also require more attention when setting your device on the pad, due to the precision of alignment of the transmitting and receiving coils that is necessary for inductive wireless charging. It can be frustrating taking the time to adjust and readjust where your phone is sitting on the charging pad before it hits that sweet spot that initiates charging your device, but the correct placement will become second nature after the first few times.