AMD recommends a minimum PSU of 350 Watts for a PC with a RX6400 GPU card.
From your other threads that you have opened it sounds like your purchased an OEM AMD PC with only just a AMD APU Processor installed. Normally in a PC with a APU and no GPU cards installed the PSU is very low wattage.
I would go to the manufacturer of your PC and find out if you can replace your low wattage PSU with a 3rd party PSU because many of these OEM AMD PC uses propriety PSU and Motherboard that are not compatible with 3rd party hardware.
To find out generally how well your PC will run with a RX6400 GPU card and a A8 APU processor go to this website and input your CPU, GPU and RAM installed. It will tell you how well it will run in various games and FPS in each games as examples: FPS & Bottleneck Calculator
if your talking about power from your house, Most if not all PSU have a switch that you can use to make the PSU compatible with either 120 Vac or 220Vac from your outlet.