What is the power distribution system on the PCB board

Usually what we show on PCB board, the power distribution system (PDS) refers to the subsystem that distributes the power of the Power Source to the devices and devices in the system that need to be powered.

PCB board design always has impedance discontinuity, how to solve it

But there is always a time when the impedance of the PCB board? cannot be continuous, what should I do?