Keyboard layout is a function of Windows. You get to select it when installing it, then can change it through the control panel at any stage. You can map additional symbols to specific keys.
I'm writing this on a laptop I bought in the USA so it has a USA keyboard, my machines at home have UK keyboards, when I was in Spain it was a Spanish keyboard; the PC beside here in Paris has a French AZERY keyboard.
If you want to change the keys it is more usual to buy a complete keyboard, depending on the make they can be changed over in under a couple of minutes with a complete of clips and a ribbon connector. You can shop around for a broken machine to strip one off or buy new.