There are types A (Japan), B (US), C (EU), D (India), E (France), F (Germany), G (UK), H (Israel), I (AU) and so on: in which all have a distinct plug shape and differences in prongs. Type A plug is just two straight prongs without a ground while Type B is nearly identical to A but with a ground connection and Type F has no ground attached to the outlet while Type E does, usually this is solved with a adapter (for electronics that are dual voltage and support 50/60Hz frequency).
However, household appliances are typically region locked in the sense of being singular voltage (like electric kettles, toasters, refrigerators, washing machines) since those are intended to not be made for travel (mainly for domestic use supporting only a single plug type) unless you have both an adapter and a transformer. You can’t just plug a 120v 60Hz Toaster (B Plug) onto a 230v 50Hz outlet (Type F socket) with an adapter alone as that’ll blow the fuse.
Most modern electronics (as in laptops, game consoles and smartphones) support dual voltage and frequencies but their default plug type is region locked, so if you’ve bought a PS5 in the UK importing it into the US (the default cable is Type G that comes with the packaging when plugging into a TV) unless you swap cable for a Type B plug but it’ll work fine. Why is there no unilateral plug type that’s “region free” when discussing plug types found in appliances.
Never seen 380v in a residential setting. I know theres a circuit for it in my building for the elevator.
the entire point of three phase circuit is that you can split it into single phase circuits without using too much wire. usually block will be wired so that 1/3 of flats is connected to one phase, but if you need to power big loads like ag tools or something like concrete mixer three phase supply can be done (415V these days, there’s upward shift in voltage)