Most of the ways I know where people make millions without hardwork are illegal and frowned upon.
The only legal way I know of is through investing. You invest a particular sum of money for an extended period and it grows at an exponential rate without you lifting a finger.
One of such investments is real estate investment where you buy a piece of property and it increases in value the longer you leave it.
You could also invest in shares, bond, etc to get the same value.