If a deceased person died without leaving a will there are standard rules in place to decide how that person's assets are distributed. The law calls this dying 'intestate'. These standard rules can be challenged, just like any will can.
The practical difficulty that arises when someone dies without leaving a will is who will administer the estate? That is a good question, and depends on the individual circumstances.
Call us on 1800 720 211 if there is no will and you are unsure what to do about it.