Here are some examples:
* Mukashi mukashi... (昔々...) This is a classic opening phrase for Japanese fairy tales, meaning "Once upon a time..."
* Mukashi no koto desu ga... (昔のことですが...) This translates to "It's a story from long ago..."
* Mukashi wa... (昔は...) This means "In the old days..."
"Mukashi" can also refer to a specific time period in the past, but it's not as precise as a date. It can also be used figuratively to refer to something that feels old-fashioned or out of date.