I'm having scrambled alphabet problems using an Apple keyboard.

Birck Cox wrote:

If I type using my Apple keyboard, Y is replaced by Z, Z by Y. What do I need to do to fix this?

If your keyboard does qwertz instead of qwerty, you have gotten German instead of US as your active input source. Go to system settings > keyboard > text input > edit > all input sources and use the minus button at the bottom to remove German or any other extra item, so that only US is on the list.

Birck Cox wrote: I had been working with German earlier today.

If you do need the German input source for some reason, by all means put it back on the All Input Sources list. You can switch between English qwerty and German qwertz easily via the Menu Bar or keyboard shortcuts Control Space or Fn/Globe.

All characters needed for German can be made from the English keyboard by either the Press and Hold Accent Menu or various option key shortcuts.

Enter characters with accent marks on Mac - Apple Support

In System Settings > Keyboard you can add and remove input sources, but you cannot determine which one is active at any given time, that to be done via the Menu Bar or keyboard.

That’s odd. Make sure the right keyboard is selected in the toolbar (if you display the keyboards there) or in System Settings > Keyboard.