An heir is an individual who is entitled to inherit the property or assets of a deceased person based on the laws of intestate succession. Intestate succession refers to the legal distribution of an estate when the deceased person did not leave a valid will.
On the other hand, a beneficiary is a person or entity who is designated to receive assets or property through a legal document called a will.
It's worth noting that in some cases, an heir can also be a beneficiary. For example, if a deceased person leaves a will and designates their child as the beneficiary of a specific asset, that child would be both an heir and a beneficiary.