What is Power Delivery?
Power Delivery (PD) is a specification for handling higher power and allows a range of devices to charge quickly over a USB connection. It operates by facilitating a conversation between two devices to negotiate a power contract so they can determine how much power can be pulled from the charger. Power Delivery starts at the 5V setting and is configurable up to 20V. Using a standard USB-C cable, it can handle up to 60W, and will go up to 100W using a designated EMCA cable.
Another point of interest regarding Power Delivery is that it allows for power to flow both ways, with no set direction based on circuit or connection. For example, if you were to connect two phones that support Power Delivery with a USB-C charging cable, one phone could charge the other and vice versa.