I've created a simple Lightning Flow that shows just one screen. That screen includes a Lightning component with one input field. (This is a very simple test case.) Then, from the Case object, I created an Action that calls the Flow. I then added the action to the standard Case page layout. When I open an existing Case record, I don't see the button I added to the page layout. I see that there may have been a change with Winter '18 that restricts Actions to specific Record Types. I don't understand what the following linked references are telling me. Is there a way I associate an Action with a Record Type?
It looks like there was a similar post on this issue a year ago, with no definitive answer: